WORKSHOP 21 OPTIMIZING PERFORMANCE OF RADIATION INTERCHANGE ANALYSIS

WS21-2 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation

WS21-3 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Objective: Modify the database of exercise_14 and the template.dat.apnd file in order to increase analysis speed and reduce file size. Rerun and monitor the analysis and compare CPU time of the run and file size to those of Exercise 14.

WS21-4 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Model Description: In this Exercise we will reopen the database created in Exercise 14 and modify the radiation viewfactor LBCs and the template.dat.apnd file. These modifications will significantly reduce the execution time of both the radiation interchange calculations as well as the thermal analysis network run. Also, the size of several of the files will be significantly reduced Any analyst who uses the radiation interchange capability of MSC.Thermal should become practiced in using the available flags and settings which will increase execution speed and reduce storage demands.

WS21-5 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Exercise Overview: 1. Open the existing database named exercise_14.db. 2. Use Loads/BCs/Modify/Radiation to modify the existing radiation boundary conditions. 3. Create a new radiation Load/BC for Surface Change the Job Name in the Analysis form to exercise_ Modify the template.dat.apnd file to include a collapse flag. 6. Submit the model for analysis and use the commands described to monitor its progress. 7. Debug, if necessary and resubmit after deleting all the files in the job named subdirectory. 8. Read in results file and plot results. 9. Compare CPU times and File sizes. 10. Quit MSC.Patran.

WS21-6 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 1: Open an Existing Database Open the existing database named exercise_14. db a. File: Open. b. Select the file named exercise_14. db from the database list box. c. Click OK. d. Clear the screen using the Reset Graphics icon. b c a

WS21-7 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 2: Modify the Existing Radiation LBC Use Loads/BCs: Modify/Radiation to modify the existing radiation boundary conditions. a. Loads/BCs: Modify/Radiation/Element Uniform. b. Select Template, View Factor for Option. c. Select for Select Set to Modify. d. Click Modify Data… e. Enter 1 for Convex Surface ID. f. Deselect Can Be Obstructing Surface. g. Click OK. h. Click Modify Application Region…. i. Delete Surface 2, so only have Surface 1 for Application Region/Select Surfaces or Edges. j. Click Add, OK, then Apply. b c d e f g h i j j i a j

WS21-8 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 3: Create a Radiation LBC Create a new radiation Load/BC for Surface 2. a. Loads/BCs: Create/Radiation/Element Uniform. b. Select Template, View Factors for Option. c. Enter Rad2 for New Set Name. d. Select 2D for Target Element Type. e. Click Input Data… f. Enter 1 for Enclosure ID. g. Enter 200 for VFAC Template ID. h. Enter 2 for Convex Surface ID. i. Deselect Can Be Obstructing Surface. j. Click OK. k. Click Select Application Region. l. Select Surface 2 for Select Surfaces or Edges. m. Click Add, OK, and Apply. a c d e f g h i j k l m m m b

WS21-9 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 4: Change Job Name Change Job Name in Analysis form to exercise_21. a. Analysis: Analyze/Full Model/Full Run. b. Change Job Name to exercise_21. a b

WS21-10 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 5: Modify Template Modify template.dat.apnd file to include the collapse flag. Use Analysis: Build Template to create a new template.dat.apnd file which includes the collapse flag entry. *=============================== VFAC VFAC *=============================== The main advantage of using COLLAPSE to collapse radiosity nodes is that this will result in a much smaller number of radiation resistors in the model. A smaller number of resistors usually means that the thermal analysis will proceed faster. In the best cases, the number of radiation resistors may be reduced by about a factor of four for 2D Cartesian or axisymmetric models and by about a factor of 16 for 3D models.

WS21-11 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 6: Submit the Model for Analysis Submit the model for analysis and use the commands described to monitor its progress. Return to the open Analysis form and check Apply. After the command Line History Window stops scrolling, change focus to the UNIX window and affect the cd exercise_21 command with a carriage return. Repeated execution of ls within the jobname subdirectory will show the progress of the analysis. Once the file vf.msg.01 appears, type $ tail –f vf.msg.01 This will provide a continuous status of the viewfactor run. When the viewfactor analysis is complete it will end with the status message Successful Execution Completed. Use the c key combination to terminate the tail function. Again input a sequence of ls commands until a stat.bin file appears in the directory list. Once you the see the stat.bin file type $ qstat c to monitor the progress of the network analysis. This command will self terminate after 20 repetitions or upon job completion. Monitor the data from the qstat command to determine the numerical status of the analysis. Check for the existence of an nr0.nrf.01 results file. If it exists the numerical analysis is complete.

WS21-12 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 7: Debug for Failed Analysis Debug, if necessary, and resubmit after deleting all the files in the job named subdirectory. If Step 6 does not yield a results file then determine what went wrong. Is there a patqb.log file? If so, then is there a patq.msg file? If there is no patqb.log file then look in the MSC.Patran Command Line History Window or in the MSC.Patran interface for any error messages. If there is a patqb.log file and no patq.msg file then look for error messages in patqb.log. If there is a patq.msg file then look for error messages in it. If there are no error messages in the patq.msg file but this analysis requests that a viewfactor run be made then is there a vf.msg file? If there is a vf.msg file then look for error messages in it. For this analysis answering the above questions should provide a clue to the problem. Once the error is found and resolved repeat the analysis. Remember, many of the files will have an extension index which has been incremented by 1, e.g. vf.msg.01 to vf.msg.02. If it is convenient, delete all the files from the job named subdirectory exercise_21 prior to resubmitting the analysis.

WS21-13 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation g c e h Step 8: Read and Plot Results Read results file and plot results. a. Analysis: Read Result/Result Entities. b. Click Select Results File… c. Navigate to directory exercise_21. d. Select file nr0.nrf.01 for available files. e. Click OK f. Click Slect Rslt Template File… g. Select pthermal_1_nodal.res_tmpl for Files. h. Click OK, then Apply. b f h a

WS21-14 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Read results file and plot results. (continued) a. Results: Create/Quick Plot. b. Select TIME: D+00S… for Select Result Cases. c. Select Temperature for Select Fringe Result. d. Click Apply. e. Select Fringe Attributes icon. f. Select Element Edges for Display. g. Click Label Style.. h. Select Fixed for Label Format. i. Use slider bar to set to 4 for Significant figures. j. Click OK, then Apply. Step 8: Read and Plot Results (Cont.) b c d e f g h i j j a

WS21-15 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Compare CPU times and file sizes. Use the qstat command in each of the job name subdirectories to find the CPU time data and record it in the following table. Use the ls –al v* command in each job name subdirectory to record the size of the vfnode.dat, vfraw.dat, and vfres.dat files in the following table. The size and speed improvement are significant. Step 9: Compare Output Files SubdirectoriesExercise_14Exercise_21 CPU Time (Sec.) Vfnode.dat (bytes) Vfraw.dat (bytes) Vfres.dat (bytes)

WS21-16 PAT312, Workshop 21, December 2006 Copyright 2007 MSC.Software Corporation Step 10: Quit MSC.Patran Quit MSC.Patran a. Select File on the Menu Bar and select Quit from the drop down menu a