Hello
I am use two "Pressure Acoustics, Transient" physics (actd & actd2) and two "Time Dependent" study (sol1(for actd) & sol2(for actd2)) and in 3D I have two regions with different initial values (numerical values for pressure) for the first physics, sol1 solves time dependent pattern from 0 to 1E-4 (second) with 1E-6 s step size. I want to use pressure pattern at 1E-4 s ( which is solved by sol1) as initial value in actd2 for the first region and initial value for the second region is a number.
I use "at(1E-4,actd.p_t)" for initial value in actd2 but Error "The at() operator cannot be used in this context." occurs.
How can I use previous solution in next physics and study as initial value?
Thank you
Perhaps you can use the following: Right-click on Study and choose Study Reference. I have used this previously to find the harmonic response for a frequency sweep (Study2), refering back to a topology optimization run for only a few frequencies (Study1). Also, under Study2->Step there is a Values of Dependent Variables where you can set which variables to use. If left in default options, the sweep gives the result for Study1 with initial conditions, whereas the input fields can be manipulated to give the sweep result using the final conditions in Study1 (i.e. for a finished optimization).
Let me know if you can used it similarly.
Component coupling operators may be useful in your case ...
Using at(1E-4,actd.p_t) function at second physic region will not work. You have to specify to the solver to pick that number from stored solution of sol1 (I assumed) and then put into the second physical region (actd2). The function taking care of this is called withsol (in COMSOL 5.3 or higher). I am not sure about older version of COMSOL; but, in COMSOL 5.3 or higher you could easily apply your condition by specifying :
withsol('sol1', actd.p_t, setval (1E-4[put the unit here s or ns] ,t)).
It would be good idea also to differentiate your 'components' into two. Since you are not using some part of your geometry at first study, it is wise to exclude them in order to decrease the total mesh size. If you do so, then you need to "map" the two components through boundary or domain which sharing same region (in contact with each other).
In multi physics option, you can un-tick one physics to and then again second time tick the same to take it into account. Please see pipe-elbow erosion example. They have did this.
have you found a solution? I saw three different ways, some change the "initial values of variables solved for", some change "initial values of variables not solved for", and some change both, any ideas which is correct? thanks !
Hello
I have same problem but I want to ask about how we can chose which part of steady state solve will take part in the time dependent solver ?
Should we use time as indicator for peak flow and pressure or there is an alternative way to use.
thank Piyapong Buahom
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