Week - 8 Mass Scaling

Aim: To study the effect of changing d2ms & tssfac on the run time

Original Clock time without mass scaling: 12 hrs 43 min. Time Step: 4.4E-05 (d2ms=-3.5E-5)

Clock time with mass scaling: 8 hrs 23 min. Time Step: 6.3E-5, % mass increase:0.14296 %(d2ms=-7E-5)

Clock time with mass scaling: 5 hrs 23 min. Time Step: 9 E-5, % mass increase:6.4233 %(d2ms=-1E-4)

Clock time with mass scaling: 5 hrs 6 min. Time Step: 9.18 E-5, % mass increase:7.4771 %(d2ms=-1.02E-4)

Explanation:

As d2ms is increased from -7E-5 to -1.00E-4 and then -1.02E-4 the percentage mass increases from 0.14296 (Timestep = 6.3E-5 and total clock time 8hrs 23min) to 6.4233 %(Timestep 9E5 and total clock time 5hrs 23min) and then 7.4771 %(Timestep = 9.18E-5 and total clock time 5hrs 6min)

This is because as d2ms increases the inertia effects increase leading greater mass and higher dt and hence lesser clock time.

To Increase the stability of the run we can change the tssfac from 0.9 to 0.6 due to which the timestep reduces but the stability of model increases without effect on mass scaling. To demonstrate this please refer to the trial below.

Clock time of last run with modified tssfac of 0.6: 7hrs 40min. Time Step: 6.12E-5, % mass increase:7.4771 % same as previous run.(d2ms=-1.02E-4)