Week - 8 Mass Scaling

Objective:- We are using mass scaling to reduce the runtime of a model and ensure the stability of mass scaling.

Procedure:-

1. Run the given file using the Ls-run.
2. Check the time taken to solve the model.
3. 
4. Estimated Time:- 38hrs 52 mins
5. Time Step Value:- 4.40E-05
6. added mass:- 0
7. Percentage increase:-0
8. DT2MS:- -3.50e-05
9. TSSFAC:-0.9
10. We got the above values from the first run.
11. Case2:- Increase the value of DT2MS and save the file and run.
12. 
13. 
14. Estimated Time:- 29hrs 35 mins
15. Time Step Value:- 4.40E-05
16. added mass:- 0
17. Percentage increase:-0
18. DT2MS:- -4.50e-05
19. TSSFAC:-0.9
20. We can observe the decrease in the duration, there is no increase in the added mass from this we can increase the DT2MS value a bit more and try.
21. Case3:- Increase the value of DT2MS and save the file and run.
22. 
23. 
24. Estimated Time:- 11hrs 06 mins
25. Time Step Value:- 1.35E-04
26. added mass:- 3.2530E+07
27. Percentage increase:-1.1432E+02
28. DT2MS:- -1.50e-04
29. TSSFAC:-0.9
30. Since we increased the value of DT2MS compared to the case-2 we can observe huge addition of mass which is not recommended.
31. Case4:- Reduce the DT2MS and save the file and run.
32. 
33. 
34. Estimated Time:- 18hrs 36 mins
35. Time Step Value:- 8.55E-05
36. added mass:- 1.2274E+06
37. Percentage increase:-4.3136E+00
38. DT2MS:- -9.50e-05
39. TSSFAC:-0.9
40. Since we decreased the value of DT2MS compared to case-3 we can observe the reduction in the mass addition and percentage is with in the control.
41. Case5:- Increase the value of DT2MS and save the file and run.
42. 
43. 
44. Estimated Time:- 17 hrs 40 mins
45. Time Step Value:- 8.55E-05
46. added mass:- 1.8277E+06
47. Percentage increase:-6.4233E+00
48. DT2MS:- -1.00e-05
49. TSSFAC:-0.9
50. Since we increased the value of DT2MS compared to case-4 we can observe the addition in the mass addition and percentage is with in the control.
51. Case6:- Increase the value of DT2MS and save the file and run.
52. 
53. 
54. Estimated Time:- 16hrs 41 mins
55. Time Step Value:- 9.26E-05
56. added mass:- 2.2778E+06
57. Percentage increase:-8.0050E+00
58. DT2MS:- -1.029e-04
59. TSSFAC:-0.9
60. Since we increased the value of DT2MS compared to case-4 we can observe the addition in the mass addition and percentage is with in the control.
61. Since we reached an optimized solution.
62. We can insert the implicit_auto & implicit_general control cards and we can remove the control_timestep card to make it an implicit solution.
63. 
64. 
65. SAve the file and run it.
66. 
67. We can observe the normal termination.
68. 
69. 

Conclusion:-

From the above 7 cases, we can say that the DT2MS value helps to decrease the termination time by increasing the mass of the system. The TSSFAC value will not have any effect on the added mass and can be used to make the system stable. The default value of TSSFAC is 0.9.

Cases	Mass scaling Value	Runtime
Case-1 Default	-3.50e-05	38hrs 52 mins
Case-2	-4.50e-05	29hrs 35 mins
Case-3	-1.50e-04	11hrs 06 mins
Case-4	-9.50e-05	18hrs 36 mins
Case-5	-1.00e-05	17 hrs 40 mins
Case-6	-1.029e-04	16hrs 41 mins
Case-7 Implicit	-	4 secs