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  • Download the HEVACOMP CFD Module
    Hevacomp CFD module Information Questions Answers Download PHOENICS News Winter 2015 Flash Version of Latest News Letter Download the HEVACOMP CFD Module HEVACOMP CFD Please email CHAM at heva cham co uk for download details for the CFD plug in

    Original URL path: http://www.cham.co.uk/hevacomp/download.php (2016-02-15)
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  • Manual domain decomposition in parallel PHOENICS
    domains in Y direction is one too Third line shows that number of sub domains in Y direction is two domain is split in Z direction on two equal or almost equal parts This simple type of manual decomposition may alternatively be achieved by adding settings to the Q1 file For example to split the domain into 8 sub domains 2 in each direction the following arrays must be set in the Q1 file LG 2 T IG 1 2 IG 2 2 IG 3 2 The logical LG 2 will instruct the splitter to by pass the automatic domain decomposition and split the domain according to the settings defined in the IG array as follows IG 1 specifies the number of sub domains in the x direction IG 2 specifies the number of sub domains in the y direction IG 3 specifies the number of sub domains in the z direction 2 Decomposition on arbitrary sizes in selected directions of one domain Second type of decomposition allows dividing of domain on non equal parts It is helpful sometimes when user has PCs with non equal parameters connected by network Therefore for better performance user wants to set more cells to more powerful PC In this case user should set three lines for example NXSD 1 38 NYSD 2 36 16 NZSD 1 28 The first numbers after sign are numbers of sub domains in current direction Next number or numbers is number of cells in current direction for each sub domain Sum of cells for all sub domains should be equal the total number of cells in each direction The sample demonstrates case when there is not splitting in X and Z direction number of cells in X direction is 38 number of cells in Z direction is 28

    Original URL path: http://www.cham.co.uk/products/manualdecomp.php (2016-02-15)
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  • Parallel PHOENICS with MPICH2
    account cfd1 password confirm Do you want this action to be persistent y n y If the cluster has been set up within a network Domain rather than a Workgroup then in the above you should also specify the domain as part of the account name For example if phoenics is the domain and cfd1 is the user account within that domain enter phoenics cfd1 The response y ensures that this action is persistent i e this registration process does not have to be repeated for each session on this workstation If Phoenics is being run across a cluster as opposed to running on a single multi core workstation then it will be useful to identify the workstations within the cluster This may be done in a Command Prompt window using smpd exe For example to include the four PCs CHAM CFD1 CHAM CFD2 CHAM CFD3 and CHAM CFD4 in a cluster we type smpd exe sethosts CHAM CFD1 CHAM CFD2 CHAM CFD3 CHAM CFD4 To check which hosts have been added to the cluster one can type smpd exe hosts The response will be a list of the workstations in the cluster While this step is not essential for running on a cluster it does mean that when you subsequently run the parallel solver you do not need to keep specifying which nodes to use for computations smpd will select the hosts from the list 6 4 Running Parallel PHOENICS 6 4 1 Running the standard parallel Earth The simplest way to launch parallel EARTH is from the VR Editor although it can be run from a Command Prompt window If a parallel PHOENICS licence has been purchased an additional sub menu Parallel Solver will appear under the Run menu option in the VR Editor Once the parallel solver is chosen a dialog box will appear on the screen where the user can either specify the number of processes to use or to specify a MPI configuration file The pulldown combo box provides the user with an option to select up to 64 processes in steps of 2 Those users who have more than 64 processors on their workstation cluster may type the appropriate number into the box The Cluster Host List portion of the dialog enables the user to select which hosts in the cluster are used for computation Here there are three options Local Only the default will just use cores on the local machine ie that on which the instance of VR Editor is running Any will use a computer assigned distribution of processes on the nodes in the cluster These must have been previously identified in the cluster see step 7 in section 6 3 above Specify in list users may select hosts from the scroll list By default this list should contain those hosts previously idenified in the cluster but one can also add to the list by using the Add button Alternatively one can supply a Machine List file which contains a list of those workstations from which to select This file is simply a text file with name of the workstations each on a separate line This mode of running the parallel solver will always launch the root process on the local machine and a convergence monitoring window will appear on screen as per the sequential solver If running across a cluster then the run will attempt to launch an instance of the solver at the same location If the default locations are used this will be C phoenics d earth d windf earexe exe If a Private Earth is to be used then this also should be copied to the equivalent directory for each of the compute nodes When running across a cluster it is important to consider the working directory on the compute nodes This is because by default mpiexec will attempt to launch the process in the equivalent directory on all the workstations So if on the head node you are working in c phoenics myprojects projectbeta then this directory should also appear on all the workstations in the cluster otherwise the run will fail As it can difficult to always remember to create the working directory on all the cluster workstations there is an alternative One can set up an environment variable PHOE WORK DIR on each of the cluster to point to an existing fixed directory e g PHOE WORK DIR C phoenics mypar runs Then all processes aside from the launching process will write their output to this location PLEASE NOTE The use of PHOE WORK DIR is not recommended if you are likely to make multiple parallel runs simultaneously This is because the second run and subsequnt runs will overwrite the working files of the first The above methods of launching the parallel solver do not allow the user to fix the number of solver instances on each workstation If you want that level of control then the user will need to use the MPI Configuration file see section 6 4 4 below 6 4 2 Automatic domain decomposition When using the default automatic domain decomposition parallel PHOENICS only differs from sequential when Earth is run the problem set up and post processing of results can be done in exactly the same way as for the sequential version A case that has been run in sequential mode can be run in parallel without any changes being made The output from a parallel PHOENICS simulation will be result and phi files having the same format as for sequential simulations 6 4 3 User specified sub domains It is also possible to by pass the automatic domain decomposition algorithm and to specify how you want to decompose the calculation domain into sub domains This can be done by setting the appropriate date for solver arrays in the Q1 file For example to split the domain into 8 sub domains 2 in each direction the following arrays must be set in the Q1 file LG 2 T IG

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr110/p_mpich2.htm (2016-02-15)
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  • Parallel PHOENICS with MS-MPI
    a Windows Firewall Security Alert When running in parallel mode it is essential that earexe is Unblocked even if you are only using the processors of the head node If mpiexec is run with an MPI configuration file instead of the executable program as the argument then there will be an additional security alert for the mpiexec program Again it is essential that this program be unblocked With the Windows Firewall the user may choose to unblock the earexe executable from the security alert dialog above one will require Administrator permissions to unblock However if you are operating across a cluster this will not be sufficient to enable Parallel Phoenics to run There are additional settings needed on both the head and compute nodes 6 6 Running Parallel PHOENICS 6 6 1 Running the standard parallel solver from the GUI The simplest way to launch the parallel solver is from the VR Editor although with MS MPI this is currently only suitable for running the solver on a single computer If a parallel PHOENICS licence has been purchased an additional sub menu Parallel Solver will appear under the Run menu option in the VR Editor Once the parallel solver is chosen a dialog box will appear on the screen where the user can either specify the number of processes to use or to specify a MPI configuration file The pulldown combo box provides the user with an option to select up to thirty two processes 6 6 2 Running parallel solver through HPC Job Manager To run the parallel solver across the HPC cluster it is best to submit the job via the Job Manager In the following scenario it will be assumed that the head node computer is called PHOE HEAD1 It will be further assumed that PHOENICS has been installed in C phoenics shared as phoenics and that the user case files will be in the directory C phoenicsData myCase1 where c phoenicsData is shared as phoenicsData Set up the case using the VR Editor on the head node Save Working files and or Exit making sure to Save changes to EARDAT file for Solver In HPC Job Manager in the Actions pane click New Job In the left pane of the New Job dialog box click Edit Tasks Point to the Add button click the down arrow then click Basic Task In the task dialog box type a name for your task Type the task command in the Command line entry box mpiexec phoe head1 phoenics d earth d windf earexe exe Specify the Working directory for your task In general a working directory should be indicated with a Universal Naming Convention UNC path not a relative or a local path In our example it will be phoe head1 phoenicsData myCase1 Specify the Standard input Standard output and Standard error file names relative to the working directory Set the minimum and maximum number of cores necessary for your job Click OK to add the task to your

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr110/p_msmpi.htm (2016-02-15)
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  • Loading of PHOENICS version 2010 on a PC with MS Windows OS
    window From the Start menu it is located under Accessories change to the mpd directory cd c Program Files MPICH mpd bin assuming the default location was chosen and run the MPICH program MPIRegister exe You will be prompted for an account and password e g mpiregister exe account cfd1 password confirm Do you want this action to be persistent y n y If the cluster has been set up within a network Domain rather than a Workgroup then in the above you should also specify the domain as part of the account name For example if phoenics is the domain and cfd1 is the user account within that domain enter phoenics cfd1 The response y ensures that this action is persistent i e this registration process does not have to be repeated for each session on this PC 5 The user may run the MPICH Configuration tool to identify the PCs in the cluster From the Start menu locate the MPICH menu the MPICH Configuration tool is available under the mpd submenu First select the hosts in your cluster on which you have installed MPICH using the Add or Select buttons In this example we have four PCs CHAM CFD1 CHAMCFD2 CHAM CFD3 and CHAM CFD4 In column two tick the final option enable localroot option by default press the yes button on that row and then press Apply You may now press OK to close the configuration tool 6 4 Windows Firewall settings 4 XP Personal Firewall With the introduction of XP Service Pack 2 the personal firewall is now activated by default If the firewall is activated then running the PHOENICS solver earexe may generate a Windows Firewall Security Alert When running in parallel mode it is essential that earexe is Unblocked even if you are only using the processors of the host PC If mpirun is run with an MPI configuration file instead of the executable program as the argument then there will be an additional security alert for the mpirun program Again it is essential that this program be unblocked With the Windows Firewall the user may choose to unblock the Earexe executable from the security alert dialog above However if you are operating across a cluster this will not be sufficient to enable Parallel Phoenics to run There are additional settings needed on both the master and slave PCs For those using the Windows XP open the Windows Firewall icon from the Control Panel then go to the Exceptions Page On the Master PC you will need to use the Add Program button to add the following programs C Phoenics d earth d windf earexe exe C Program Files MPICH mpd bin mpiconfig exe C Program Files MPICH mpd bin mpirun exe You may also use the Change scope button to restrict access to My network subnet only On each of the slave PCs you will need to add the programs C Phoenics d earth d windf earexe exe C Program Files MPICH mpd bin mpd exe Users of other personal firewall will need to unblock the above programs in a manner suitable for their firewall software 6 5 Running Parallel PHOENICS 6 5 1 Running the standard parallel Earth The simplest way to launch parallel EARTH is from the VR Editor although it can be run from a Command Prompt window If a parallel PHOENICS licence has been purchased an additional sub menu Parallel Solver will appear under the Run menu option in the VR Editor Once the parallel solver is chosen a dialog box will appear on the screen where the user can either specify the number of processes to use or to specify a MPI configuration file The pulldown combo box provides the user with an option to select up to thirty two processes Those users who have more than thirty two processors on their PC cluster may type the appropriate number into the box This method does have its limitations though it does require that each node in the cluster must have been previously identified using the MPICH Configuration tool see step 5 in section 6 3 each node has a local copy of Earth If a full installation of Phoenics has not been made then there must be a copy of the Earth executable at phoenics d earth d windf earexe exe If a Private Earth is to be used then this also should be copied to the working directory for each of the slave processes 6 5 2 Configuration File The MPI configuration file option gives a more flexible way of launching the parallel solver Assuming we have PHOENICS installed on each PC in the cluster the following config file will use the local earexe exe to run a single process on each of the four PCs exe c phoenics d earth d windf earexe exe hosts cham cfd1 1 cham cfd2 1 cham cfd3 1 cham cfd4 1 Example configuration files config2 and config4 are provided as part of the PHOENICS installation in directory phoenics d utils d windf The following file config4 is for use on a cluster where PHOENICS is installed only on the master PC exe cham cfd1 phoenics d earth d windf earexe exe hosts cham cfd1 2 cham cfd2 2 This file is for use with a run command such as runcl4 issued on cham cfd1 with chamcfd2 as the other machine in the cluster The first line specifies the executable program earexe and the text phoenics on that line is the shared name of the actual phoenics folder e g c phoenics The lines following the hosts line list the machines that are to be used and the number of processes to be used on each in this case 2 If the executable program is to be different on each host then this line may take an optional third parameter indicating the executable program as it will be seen from the machine in question Note that the first host machine should

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  • TR326: VR Object Management
    the physical spacing between objects or groups in that direction The spacing is set as the distance between origins it should be one gap between objects plus one object width if the objects are not to overlap Offsets sets the offsets in the other two directions By setting non zero values for one or more of the offsets diagonal lines and arrays can be easily created If one or more of the objects to be arrayed is constrained by the domain and Dimension Pitch or Dimension Offset is too large to fit in the domain a warning message is displayed and the option to adjust the pitch or offset is offered However if the Pitch is 2 it is assumed that the user wanted to duplicate the object at the other end of the domain and the pitch is automatically adjusted to fit If the object or objects to be arrayed are all unconstrained no checks are made on the final positions of the created objects Cancel closes the dialog without performing the arraying operation Apply performs the operation without closing and OK performs the operation and closes Select All Selects all objects except the domain in the object management panel Refresh It is possible for the object management to become out of sync with the current status of the model in these cases use refresh to update its contents Close Closes the object management panel Object Management Action Menu Open object dialog Hide object Reveal object Delete object Modify colour Object Wireframe Object affects grid Object constrained by domain Object selectable Move to object centre Surface vectors Surface contours Dump surface values Dump object profile Show nett sources Open object dialog This opens the object dialog box for the current object The current object is the one highlighted in the list If more than one object has been selected the dialog box for the last object to be selected is opened When the object dialog is closed the changes made can be optionally propagated through all the other selected objects which are of the same type Care should be taken when propagating changes to ensure that unwanted changes are not made for example propagating changes through a group of INLET objects where some are side High and some are side Low will result in all of them taking the side of the one whose dialog has been displayed Hide object s This hides makes invisible all the currently selected objects Reveal object s This reveals makes visible all the currently selected objects Delete object s This deletes all the currently selected objects The user will be prompted for confirmation before objects are deleted Objects cannot be undeleted Modify colour Opens the object dialog for the current object on the options page click on the object colour button to modify the colour The object transparency may also be set from here When the object dialog is closed the colour changes will be applied to all selected objects Object Wireframe Check

    Original URL path: http://www.cham.co.uk/phoenics/d_polis/d_docs/tr326/obj-man.htm (2016-02-15)
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  • TR326: Main Menu
    or removed as needed Pressure and velocity must be ON before it becomes possible to select Multi Phase or Free Surface models Models Solution For Swirl If the geometry is axi symmetrical two dimensional in the Y Z plane this option switches on the solution for the swirl component of velocity This button is only present for cylindrical polar geometries Models Free Surface Models The available free surface models are Scalar equation Height of liquid The Scalar Equation Method SEM is good for overturning or breaking interfaces but is restricted to very small time steps Height of Liquid HOL can run steady state or with larger time steps but cannot deal with overturning interfaces See also the Lectures on Scalar Equation Method and Height of Liquid Models Energy Equation The energy equation can be solved in one of two forms Temperature TEM1 TEM2 or Enthalpy H1 H2 The enthalpy form is often more suited to combustion applications the temperature form to conjugate heat transfer Internally the equation is always cast in enthalpy form so the units of the sources are always Watts Models Energy Equation Total Static By default the Temperature form is set to Total the enthalpy form to Static The static form includes the substantial derivative of the pressure and the kinetic heating terms in the energy conservation equation as additional source terms the Total form does not If the flow is highly compressible high Mach number the Temperature form should be switched to Static otherwise incorrect solutions will be obtained This is because all the property formulae require the static temperature The Enthalpy form can be used in Total form as long as a suitable temperature derivation is selected in the properties panel Models Turbulence Models The available turbulence models are divided into the following groups LAMINAR The flow is laminar and there is no turbulence model CONSTANT EFFECTIVE The turbulent viscosity is constant The default setting is 200 times the laminar viscosity LVEL Generalised length scale zero equation model useful when there are many objects and the grid is coarse KEMODL Classical two equation high Reynolds number k e model KOMODL Kolmogorov Wilcox two equation k f model Useful for transitional flows and flows with adverse pressure gradients USER User defined model for advanced users KE Variants Several variants of the K E model usually giving enhanced performance for recirculating flow KECHEN Chen Kim two equation k e model Gives better prediction of separation and vortexes KERNG RNG derived two equation k e model Gives better prediction of separation and vortexes However the user is advised that the model results in substantial deterioration in the prediction of plane and round free jets in stagnant surroundings KEMMK Murakami Mochida and Kondo k e model for flow around bluff bodies as encountered for example in wind engineering applications KEKL Kato Launder k e model for flow around bluff bodies as encountered for example in wind engineering applications KEMODL YAP k e model with Yap correction for separated flows TSKEMO Two scale k e model for flows in which there is an appreciable time lag between the turbulent production and dissipation processes Low Re models Several Low Reynolds Number variants of the K E model KEMODL LOWRE Lam Bremhorst low Reynolds version of k e KEMODL LOWRE YAP Lam Bremhorst low Reynolds k e with Yap correction for separated flows KECHEN LOWRE Low Reynolds variant of Chen Kim model KEMODL 2L Two layer k e model which uses the high Re k e model only away from the wall in the fully turbulent region and the near wall viscosity affected layer is resolved with a one equation model involving a length scale prescription This saves mesh points and improves convergence rates KOMODL LOWRE Low Reynolds Kolmogorov Wilcox model Others A range of models from simple one equation models to Reynolds Stress REYSTRS including a Sub Grid Scale LES model SGSMOD MIXLEN Prandtl mixing length model Simple model for unbounded flows MIXLEN RICE Mixing length model for bubble column reactors KLMODL Prandtl energy model One equation k l model for wall dominated flows KWMODL Saffman Spalding two equation k vorticity model REYSTRS Reynolds stress model SGSMOD Smagorinsky sub grid scale LES model with wall damping SGSMOD NOWD Smagorinsky sub grid scale LES model with no wall damping SGSMOD VDWD with Van Driest wall damping function 2FLUID Two fluid model MFLUID Multi fluid model All models are described in the POLIS Encyclopaedia under Turbulence where each has its own descriptive article Brief advice use the simplest model which produces realistic results In many cases the CHEN KIM model provides a reasonable compromise between accuracy and economy If there are many walls obstacles present the LVEL model will be even more economical and also more accurate for coarse grids Models Radiation Models The following radiation models are available 6 Flux Radiosity Immersol They are described in full in the PHOENICS Encyclopaedia under Radiative Heat Transfer in PHOENICS WARNING The 6 Flux and Radiosity models are not yet fully implemented in the Menu especially with regard to the boundary conditions Please use the User defined object attribute to set the boundary conditions described in POLIS The IMMERSOL model is fully implemented Models Combustion Models The following combustion models are available 3 GASES Simple Chemically Reacting System SCRS mixing controlled or kinetically controlled 7 GASES Extended SCRS Wood Wood combustion model Coal Coal combustion model Oil Oil combustion model Chemkin Interface to Sandia Labs CHEMKIN program They are described in the PHOENICS Encyclopaedia under Combustion Reaction SCRS Extended Simple Chemically reacting System CHEMKIN Interface There are examples in the Chemical reaction library WARNING Only the 3 GASES model is fully implemented in the Menu The remaining models are not yet implemented in the Menu Solution of the required variables can be activated through the Solution control Extra variables button below Please use the user defined object attribute to set the boundary conditions described in POLIS Models Solution Control Extra Variables Image SOLUTION CONTROL EXTRA VARIABLES This panel gives options to Activate storage of user named variables enter a name up to 4 characters in STORE box and click Apply Activate solution of user named variables enter a name up to 4 characters in SOLVE box and click Apply Set the solution control switches SOLUTN command for all stored and solved variables The settings are Store create a 3D store which then appears in the solution file PHI for plotting Solve solve the variable implies STORE Whole field solve using whole field solver when Y solve using slab wise solver when N Point by point solve using point by point solver when Y solve using slab wise or whole field solver when N Explicit use explicit formulation for transient term when Y implicit formulation when N Harmonic use harmonic averaging for diffusion coefficients when Y arithmetic averaging when N Select the linear equation solver to use for each variable The default is a Stone type solver with a conjugate residuals gradient solver as an alternative Note that the conjugate residuals solver should not be used for the temperature TEM1 equation if the grid contains cut cells Set the terms in the equation for each variable TERMS command The settings which are on a separate panel are Built in source Convection Diffusion Transient Phase 1 variable Interphase transfer See the POLIS Encyclopaedia entries on SOLUTN and TERMS for more information Models Advanced User Options This panel gives access to PIL settings from Groups 7 and 8 which are not covered by the other sub menus of this panel Models Edit InForm 7 This starts the In Form editor with Group 7 selected as the current Group Full details can be found in INFORM TR 003 Models Edit InForm 8 This starts the In Form editor with Group 8 selected as the current Group Full details can be found in INFORM TR 003 Main Menu Properties From this panel the main domain material can be chosen from the CHAM supplied property libraries The domain material is the material that initially fills the entire solution domain Regions of the domain can then be filled with other fluids or solids by creating BLOCKAGE objects and selecting the required material for them The individual properties loaded from the library for the domain fluid can then be edited changed This is not possible for the properties used for blockages If a blockage is assigned the domain material it will automatically pick up the properties specified here The reference pressure and temperature values are always added to the calculated pressure and temperature before use in property calculations The reference temperature is set by choosing Centigrade reference temperature is 273 or Kelvin reference temperature is 0 for Temperature units Image PROPERTIES using Property Tables The Ambient pressure and Ambient temperature entries set the pressure and temperature prevailing outside the domain These values can be used if desired to set the pressure and temperature at all INLET WIND WIND PROFILE OUTLET FAN and PRESSURE RELIEF objects When Initialise from ambient is set ON the default the initial values of pressure P1 and temperature TEM1 are always made consistent with the ambient values set here When Set buoyancy from ambient is ON the default the reference temperature for Boussinesq buoyancy is set to the ambient temperature or for density difference buoyancy the reference density is calculated from the ambient pressure and temperature The Property storage button allows the field values of the properties to be placed in the EARTH output file PHI so that they can be plotted in the viewer Turning the property tables OFF allows the individual properties to be set directly Image PROPERTIES not using Property Tables This panel is also accessed from the Edit properties of current material button on the previous figure For each property a pull down list of all available options is provided The available options are listed in Encyclopaedia Main Menu Initialisation Image INITIALISATION This panel provides options to Activate a restart run Set all initial values to default This is 1 0E 10 for all variables except R1 R2 RS 0 5 EPOR NPOR HPOR VPOR 1 0 PRPS 1 0 Set individual whole domain initial values for all stored and solved variables If Initialise from ambient is ON on the Properties panel the initial values of pressure P1 and temperature TEM1 will be grayed out and set to AMBIENT as they will be taken from the ambient values To enter other values Initialise from ambient must be set to OFF Start the In Form editor with Group 11 selected as the current Group Full details can be found in INFORM TR 003 Unless explicitly set in this panel or set to ambient initial values for Temperature Enthalpy turbulence model quantities and solved for passive scalars will be taken from the inlet values supplied at the first inlet defined NB When solving for passive scalars where there is one inlet with a finite inlet value and one or more inlets or outlets with a value of 0 0 it can be important to set the initial value explicitly to 0 0 in case the domain is initialised to the finite inlet value If the inlet value of a scalar is 1 0 but the majority of the domain is filled with scalar 0 0 it is very important to explicitly initialise the relevant scalar s to zero If there are more than five stored solved variables the and buttons can be used to scroll through all available variables Although the names of the restart and cut cell files may be displayed as upper case the Earth solver will convert them to lower case If Restart cut cell values is set to NO the values in the cut cells will retain their initial values as set here on restart and the named file will not be read This is useful when restarting a PARSOL T run from a PARSOL F run when the pbcl dat file will be empty It can also help avoid problems restarting parallel runs when the processors cannot agree on how many cut cells there are Main Menu Sources Image SOURCES Panel This panel allows the creation of whole domain sources which are not attached to an object All sources or boundary conditions which do not apply to the whole domain must be attached to an object and set through the appropriate object attribute dialog box The Cyclic boundary conditions button gives the options Turn cyclic boundaries ON for all IZ slabs Turn cyclic boundaries OFF for all IZ slabs Turn cyclic boundaries on and off for individual slabs Cyclic boundaries are then imposed between the first and last rows of cells in the IX direction for the slabs indicated The MOFOR ON OFF button which only appears for Transient cases activates the Moving Frames Of Reference model which allows objects to move through the domain When turned ON two extra buttons are displayed One allows the user to browse for the MOF file and the other to edit it using the currently selected file editor The MOF file controls the motion of the objects For more details click here The panel also allows built in whole field sources to be set such as Buoyancy The following buoyancy options are available Constant Density difference Boussinesq Approximation Linear in 2 scalars All are described in the Encyclopaedia under Gravitational body forces In brief Option 1 applies the full gravitational force Option 2 uses a reference density and should be used if the density is not constant Option 3 uses a reference temperature and should be used if the density is constant but the temperature is variable Option 4 allows the buoyancy force to be a function of any two solved scalars If Set buoyancy from ambient on the Properties panel is set to ON the values needed for Options 2 and 3 will be taken from the ambient temperature and pressure set there Rotating co ordinate system Potential flow Coriolis forces To create a new whole field source click on Advanced settings PIL If this is not visible click on Page down to show the next page of options Image WHOLE FIELD SOURCES Enter the name of the PATCH in the New box and click Apply A new PATCH will be created the Type Coefficient and Value can now be set as required Clicking on PATCH number will cycle through the available Patches The and symbol next to Variable scrolls through the list of available variables if there are more than five To start the In Form editor with Group 13 selected as the current Group click on Edit InForm 13 on the main sources panel Full details can be found in INFORM TR 003 Main Menu Numerics Image NUMERICS The main entries on this panel allow the total number of iterations sweeps over the whole domain and the global convergence criterion to be set In transient cases the Vary with time button leads to a dialog from which the number of sweeps per time step can be changed with time or time step Up to 15 bands of sweep settings can be made If more are required or the conditions for variation are more complex InForm can be used The submenus give options to Set relaxations Set more detailed iteration control and select solver type Set upper and lower limits on the values allowed for variables Select higher order differencing schemes for convection Start the In Form editor with Group 15 16 17 or 18 selected as the current Group Full details can be found in INFORM TR 003 Numerics Relaxation Settings Image Default RELAXATION SETTINGS Relaxation is a technique for slowing down possibly excessive rates of change It does not affect the final solution In many cases convergence will be very hard to obtain without suitable relaxation settings The relaxation methods available are described in the Encyclopaedia article on RELAX The default relaxation settings turn the Automatic Convergence Control CONWIZ T in the Q1 ON MAXINC sets the maximum increment change from iteration to iteration for each variable Reference velocity sets a typical velocity in the domain usually based on a typical inlet velocity Reference length is a typical length scale for the case usually based on the domain size The two reference quantities are used to estimate an initial timescale In many cases the default values work quite well For large scale external aerodynamics for example flow over a city where the domain may be kilometers in size it can be very important to set the reference length to an average domain size otherwise convergence may be unacceptably slow The WIND object will do this automatically otherwise the user should do so manually In this mode any false time step settings for velocities are ignored the solver will set linear relaxation of 0 5 for all velocities that have false time step relaxation If the relaxation for velocities is switched to LINEAR the user set values will be used If no settings are made for the other variables the solver will set linear relaxation of 0 5 except Temperature TEM1 which is set to 0 25 For fire simulations the maximum increment for temperature TEM1 should be reduced from the default value of 1000 deg sweep to say 10 deg sweep otherwise convergence may still be difficult If the expected velocities are very small the maximum increments for the velocity components should also be reduced If a FIRE object only available in FLAIR is detected and the relaxation for TEM1 is the default no user setting has been made the maximum increment for Temperature is automatically reduced to 10 deg sweep Reset solution defaults resets all the solver control variables to their default values so that the Automatic Convergence Control can operate in full If the Automatic Convergence Control is turned off the relaxation settings can be set individually Image Manual RELAXATION SETTINGS Typical values for false time step relaxation may

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  • TR326: VR-Editor Q1 Implementation
    type where for Cartesian cases velocity type is one of ROT X rotate about X axis ROT Y rotate about Y axis ROT Z rotate about Z axis The location of the axis is set by the object rotation centre If this line is absent but the velocity line is present the object is not rotating but sliding or for Polar cases one of ANG VEL angular velocity in radians s ANG MOM angular momentum CART VEL Cartesian components of the velocity vector in m s VEL Grid directed velocity components in m s In all cases the value of the velocity is set by OBJ VELOCITY velx vely velz where velx vely and velz are the X Y and Z direction components Wall function If line not present global value used OBJ WALLCO Law Where Law is one of Default Blasius Logarithmic Generalised Logarithmic Fully rough Solar absorption factor If a SUN object is active the fraction of the incident solar radiation absorbed by this blockage is set by OBJ SOL ABSORB Factor where Factor is a value between 0 and 1 0 If the line is not present 1 0 is assumed Inlet Object type OBJ TYPE INLET Inlet with domain fluid OBJ PRESSURE Pval OBJ PRESSURE 2 Pval Pval may be the character string P AMBIENT to indicate the value set for P AMBIENT in the domain section This is the default Inlet with user set density OBJ DENSITY RHOin OBJ DENSITY RHOin R1in OBJ DENSITY 2 RHOin 2 R2in Inlet with Heavy fluid SEM or HOL OBJ FLUID 1 0 Inlet velocities OBJ VELOCITY Vel X Vel Y Vel Z OBJ VELOCITY 2 Vel X 2 Vel Y 2 Vel Z 2 OR Inlet Volume Flux OBJ VOLUFLOW VOLin OBJ VOLUFLOW 2 VOLin 2 OR Inlet Mass Flux OBJ MASSFLOW MASSin OBJ MASSFLOW 2 MASSin 2 Inlet temperature OBJ TEMPERATURE Tin OBJ TEMPERATURE 2 Tin 2 Tin and Tin 2 may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default Inlet Scalar OBJ INLET scal Cin where scal is one of the SOLVEd scalars One such line for each scalar with an inlet value Inlet Turbulence User set OBJ KE IN KEin OBJ EP IN EPin OR Inlet Turbulence Intensity OBJ TURB INTENS Tintens Emissivity OBJ EMISSIVITY Emiss Area Ratio OBJ AREA RATIO area ratio If the line is absent a value of 1 0 is assumed Object side OBJ OBJECT SIDE HIGH If the line is absent LOW is assumed HIGH can be 1 LOW can be 0 Acts as export OBJ EXPORT file name Acts as Import OBJ IMPORT file name ANGLED IN Object type OBJ TYPE ANGLED IN Inlet with domain fluid OBJ PRESSURE Pval OBJ PRESSURE 2 Pval Pval may be the character string P AMBIENT to indicate the value set for P AMBIENT in the domain section Inlet with user set density OBJ DENSITY RHOin OBJ DENSITY RHOin R1in OBJ DENSITY 2 RHOin 2 R2in Inlet with Heavy fluid SEM or HOL OBJ FLUID 1 0 Inlet velocities OBJ VELOCITY Vel X Vel Y Vel Z OBJ VELOCITY 2 Vel X 2 Vel Y 2 Vel Z 2 OR Inlet Volume Flux OBJ VOLUFLOW VOLin OBJ VOLUFLOW 2 VOLin 2 OR Inlet Mass Flux OBJ MASSFLOW MASSin OBJ MASSFLOW 2 MASSin 2 OR Normal Velocity OBJ NORMAL VEL VELin OBJ NORMAL VEL 2 VELin 2 Inlet temperature OBJ TEMPERATURE Tin OBJ TEMPERATURE 2 Tin 2 Tin and Tin 2 may be the character string P AMBIENT to indicate the value set for P AMBIENT in the domain section This is the default Inlet Scalar OBJ INLET scal Cin where scal is one of the SOLVEd scalars One such line for each scalar with an inlet value Inlet Turbulence User set OBJ KE IN KEin OBJ EP IN EPin OR Inlet Turbulence Intensity OBJ TURB INTENS Tintens Emissivity OBJ EMISSIVITY Emiss Area Ratio OBJ AREA RATIO area ratio If the line is absent a value of 1 0 is assumed Linked Angled in OBJ LINK status Status can be PREVIOUS or NEXT indicating the immediately preceding or immediately following Angled in object which need not be the adjacent object in the list If the line is absent no linkage is assumed Linked Angled in Heat source OBJ ADDQ Q where Q is the additional heat in W added to the fluid passed between the two linked Angled ins If the LINK flag is not set this setting is ignored Wind Object type OBJ TYPE WIND Settings when a weather file is not being used External pressure OBJ PRESSURE Pext Pext is the external atmospheric pressure in Pascals If Set buoyancy from ambient on the Main Menu Properties panel is ON then the reference pressure PRESS0 will be reset to this value the Ambient pressure will be set to zero If the Ideal Gas Law is used for density the reference density used for buoyancy BUOYD will be recalculated using this pressure and the set external temperature If the density is constant the reference temperature for buoyancy BUOYE will be reset to the external temperature External temperature OBJ TEMPERATURE Text Text is the external atmospheric temperature in Centigrade If Set buoyancy from ambient on the Main Menu Properties panel is ON the Ambient temperature will be reset to Text Wind with density is OBJ DENSITY RHOin If the line is missing domain fluid is assumed Pressure coefficient linear OBJ COEFFICIENT Coef The default setting is for a linear coefficient with a value of 1000 This keeps the internal pressure very close to the set external pressure Pressure coefficient quadratic OBJ COEFFICIENT Coef QUADRATIC When a quadratic coefficient is used it represents the number of velocity heads lost crossing the domain boundaries Wind speed at reference height OBJ VELOCITY Velocity The default wind velocity is 10m s Wind direction relative to North OBJ WIND DIR angle By default the wind blows from the North so the angle is zero Angle between north facing axis and North OBJ AXIS DIR angle By default the Y axis points North so the angle is zero External temperature OBJ TEMPERATURE Tin Tin may be a real value or may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default The default ambient temperature is 20C Inlet profile type Logarithmic OBJ PROFILE Logarithmic The default profile is logarithmic Inlet profile type Power law and exponent OBJ PROFILE Power law OBJ POWER EXPONT al alpha Reference height for wind speed OBJ REF HEIGHT Zr The default reference height for the velocity is 10m Roughness height OBJ RGHNS HEIGHT Z0 The default roughness height is 0 0002m which is appropriate for Open Sea Vertical direction OBJ UP DIR X Y or Z The default UP direction is Z External temperature for radiative link OBJ T EXT Text Text may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default It may also be a real number Include SKY boundary OBJ SKY YES NO If the line is missing NO is assumed Include GROUND boundary OBJ GROUND YES NO If the line is missing NO is assumed OBJ GROUND TEMP Tground Tground may be the character string ADIABATIC to indicate that there is no heat loss to the ground This is the default It may also be a real number indicating the ground temperature in C OBJ GROUND EMIS Emiss The default surface emissivity for the ground is 1 0 OBJ SOL ABSORB Factor where Factor is a value between 0 and 1 0 If the line is not present 1 0 is assumed When a weather file is being used some of the flags are not written and are replaced by some new ones OBJ WEATHERFILE filename where filename is the name of the weather file including the epw extension If the file is not in the current working directory the full path to the file must be given Note that if WIND and SUN are both set to use a weather file they will both use the same weather file and will both use the same date and time of day OBJ DATE day month year The day is set as an integer The month as one of Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov or Dec The year is given in full e g 2012 For example 1 Apr 2011 OBJ TIME hour minute second The hour is given in the 24hr system Minutes and seconds are integers in the range 0 60 For example 13 30 00 denotes half past one in the afternoon The following flags are not written as their values are taken from the weather file PRESSURE VELOCITY WIND DIR TEMPERATURE GROUND TEMP WIND PROFILE OBJ PRESSURE Pval Pval may be the character string P AMBIENT to indicate the value set for P AMBIENT in the domain section This is the default Wind profile with density is OBJ DENSITY RHOin Wind speed velocity components at reference height OBJ VELOCITY X component Y component Z component Inlet temperature OBJ TEMPERATURE Tin Tin may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default Inlet profile type Logarithmic OBJ PROFILE Logarithmic Inlet profile type Power law and exponent OBJ PROFILE Power law OBJ POWER EXPONT alpha Reference height for wind speed OBJ REF HEIGHT Zr Roughness height OBJ RGHNS HEIGHT Z0 Vertical direction OBJ UP DIR X Y or Z External temperature for radiative link OBJ T EXT Text Text may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default Object side OBJ OBJECT SIDE HIGH If the line is absent LOW is assumed HIGH can be 1 LOW can be 0 Outlet Object type OBJ TYPE OUTLET External pressure OBJ PRESSURE Pext Pext may be the character string P AMBIENT to indicate the value set for P AMBIENT in the domain section This is the default Coefficient in fixed pressure patch linear coefficient OBJ COEFFICIENT Coef default 1 0E 3 OBJ COEFFICIENT 2 Coef 2 default 1 0E 6 Coefficient in fixed pressure patch quadratic coefficient OBJ COEFFICIENT Coef QUADRATIC OBJ COEFFICIENT 2 Coef 2 QUADRATIC External Temperature OBJ TEMPERATURE Text OBJ TEMPERATURE 2 Text 2 Text and Text 2 may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default External turbulence OBJ TURBULENCE KEext EPext External velocity OBJ VELOCITY Vel X Vel Y Vel Z OBJ VELOCITY 2 Vel X 2 Vel Y 2 Vel Z 2 If the external velocity in any direction is IN CELL it is echoed here as SAME If it is DEDUCED it is echoed as DEDUCED In earlier versions it was echoed as GRND1 This setting is still accepted For DEDUCED two extra lines may appear OBJ VELIN vin OBJ VELIN 2 vin2 where vin is the initial guess for the external velocity normal to the outlet If the line is absent a value of zero is assumed OBJ RELAX relax OBJ RELAX 2 relax2 where relax is a liner relaxation factor used to slow down the rate of change of the deduced external velocity If the line is absent a value of 0 3 is assumed If VOUT and VOU2 for two phase case is STOREd the deduced velocity is made available for plotting in the Viewer External Scalar OBJ OUTLET scal val where scal is one of the SOLVEd scalars and val is the value One such line for each scalar with an external value Note that In Cell is echoed as SAME Emissivity OBJ EMISSIVITY Emiss External temperature for radiative link OBJ T EXT Text Text may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default Area Ratio OBJ AREA RATIO area ratio If the line is absent a value of 1 0 is assumed Object side OBJ OBJECT SIDE HIGH If the line is absent LOW is assumed HIGH can be 1 LOW can be 0 Acts as export OBJ EXPORT file name Acts as Import OBJ IMPORT file name ANGLED OUT Object type OBJ TYPE ANGLED OUT External pressure OBJ PRESSURE Pext Pext may be the character string P AMBIENT to indicate the value set for P AMBIENT in the domain section This is the default Coefficient in fixed pressure patch linear coefficient OBJ COEFFICIENT Coef default 1 0E 3 OBJ COEFFICIENT 2 Coef 2 default 1 0E 6 Coefficient in fixed pressure patch quadratic coefficient OBJ COEFFICIENT Coef QUADRATIC OBJ COEFFICIENT 2 Coef 2 QUADRATIC External Temperature OBJ TEMPERATURE Text OBJ TEMPERATURE 2 Text 2 Text and Text 2 may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default External turbulence OBJ TURBULENCE KEext EPext Set External velocity OBJ VELOCITY Vel X Vel Y Vel Z OBJ VELOCITY 2 Vel X 2 Vel Y 2 Vel Z 2 OR Deduced External velocity OBJ VELOCITY DEDUCED OBJ VELOCITY 2 DEDUCED OBJ VELIN vin OBJ VELIN 2 vin2 OBJ RELAX relax OBJ RELAX 2 relax2 where vin is the initial guess for the external velocity normal to the outlet If the line is absent a value of zero is assumed Relax is a liner relaxation factor used to slow down the rate of change of the deduced external velocity If the line is absent a value of 0 3 is assumed If VOUT and VOU2 for two phase case is STOREd the deduced velocity is made available for plotting in the Viewer OR In cell External velocity OBJ VELOCITY IN CELL OBJ VELOCITY 2 IN CELL OR Normal External velocity OBJ VELOCITY NORMAL OBJ VELOCITY 2 NORMAL External Scalar OBJ OUTLET scal 4 000000E 00 where scal is one of the SOLVEd scalars One such line for each scalar with an external value Note that In Cell is echoed as SAME Emissivity OBJ EMISSIVITY Emiss External temperature for radiative link OBJ T EXT Text Text may be the character string T AMBIENT to indicate the value set for T AMBIENT in the domain section This is the default Area Ratio OBJ AREA RATIO area ratio If the line is absent a value of 1 0 is assumed Sun Object type OBJ TYPE SUN Angle between north facing axis and North OBJ AXIS DIR angle where angle can be between 0 360 or the character string FROM WIND indicating that the angle should be taken from the first WIND object Vertical direction OBJ UP DIR Z At present the SUN object only works with Z as the Upright direction As the default Up direction is Z this is usually not a problem When a weather file is not in use the following flags are written Direct Solar radiation OBJ Q DIRECT Qdir where Qdir is the direct solar radiation in W m 2 It may also be the character string ALTITUDE indicating that the direct radiation should be calculated from the solar altitude The direct solar radiation is obtained from a polynomial fit to table A2 24 of The CIBSE Guide Volume A Design Data Diffuse Solar radiation OBJ Q DIFFUSE Qdif where Qdif is the diffuse solar radiation in W m 2 It may also be the character string ALTITUDE indicating that the direct radiation should be calculated from the solar altitude When set to ALTITUDE an extra line is needed OBJ SKY condition where condition is CLEAR or CLOUDY This determines how the diffuse radiation is calculated The diffuse solar radiation is obtained from a polynomial fit to table A2 25 of The CIBSE Guide Volume A Design Data Latitude of location OBJ LATITUDE latit where latit is the latitude of the location The Equator is at 0 degrees the Northern hemisphere is 0 to 90 at the North pole and the Southern is 0 to 90 at the South pole Date OBJ DATE day month year The day is set as an integer The month as one of Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov or Dec The year is given in full e g 2012 For example 1 Apr 2011 Time OBJ TIME hour minute second The hour is given in the 24hr system Minutes and seconds are integers in the range 0 60 For example 13 30 00 denotes half past one in the afternoon When a weather file is in use OBJ WEATHERFILE filename where filename is the name of the weather file including the epw extension If the file is not in the current working directory the path to the file must be given Note that if SUN and WIND are both set to use a weather file they will both use the same weather file and will both use the same date and time of day The following flags are not written as their values are taken from the weather file Q DIRECT QDIFFUSE SKY Plate Object type OBJ TYPE If line not present global value used OBJ ROUGH val Wall function for external plate If line not present global value used OBJ WALLCO Law Where Law is one of Default Blasius Logarithmic Generalised Logarithmic Fully rough Frictionless External Plate with heat Source OBJ heat source val1 val2 where heat source is as in Table 1 above except that the fixed flux can be total for the object or per unit area Internal fully blocked plate OBJ TYPE PLATE OBJ POROSITY 0 000000E 00 Internal Plate with heat Source OBJ SIDE BOTH or HIGH or LOW depending on which side has the heat source OBJ heat source L val1

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