How to specify time varying wall velocity ?
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User wants to run an unsteady case and specify a time-varying velocity to the wall. The case corresponds to an aircraft that is slowing down on the runway. The incoming velocity boundary can be specified as function of time using DEFINE_PROFILED UDF but there is no UDF hookup to specify the wall velocity to vary as function of time. How to do this ? Can write a Scheme but UDF may be easier. User can write a DEFINE_ADJUST UDF which will update the wall speed `internally' according to user specified time variation. Inside the UDF, the wall speed can be updated according to: THREAD_VAR(tf).wall.translate_mag = vel; Other relevant parameters: THREAD_VAR(tf).wall.origin[0] THREAD_VAR(tf).wall.origin[1] THREAD_VAR(tf).wall.origin[2] THREAD_VAR(tf).wall.axis[0] THREAD_VAR(tf).wall.axis[1] THREAD_VAR(tf).wall.axis[2] THREAD_VAR(tf).wall.translate_mag THREAD_VAR(tf).wall.translate_dir[0] THREAD_VAR(tf).wall.translate_dir[1] THREAD_VAR(tf).wall.translate_dir[2] THREAD_VAR(tf).wall.omega THREAD_VAR(tf).wall.u THREAD_VAR(tf).wall.v THREAD_VAR(tf).wall.w The following is an example. %---------------------------------------------------------------------------------% DEFINE_ADJUST(myadjust,domain) { int zoneID; float tm,Vel; Thread *tf; zoneID = 3; tm = RP_Get_Real("flow-time"); Vel = 0.7 + 77.7*tm; /* ... specify the velocity as function of time ...*/ tf = Lookup_Thread(domain,zoneID); THREAD_VAR(tf).wall.translate_mag = Vel; } |
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