# Vibrating / Deforming Wall UDF

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 January 15, 2004, 09:11 Vibrating / Deforming Wall UDF #1 Qureshi Guest   Posts: n/a After getting the UDF Tutorial running, now I am back on to my problem. I have to study the effects of vibrating membrane (as a wall) in a pipe. I've to make a function and then UDF for that function. ] Anyone out there working on such problem? I hope that I get some guideline with it. The tutorials and the UDF users guide are not much of the help as they just identify the basic requirement of a UDF.

 January 15, 2004, 20:31 Re: Vibrating / Deforming Wall UDF #2 ccc Guest   Posts: n/a hi Qureshi, my problem is about vibrating wings, similiar to yours and so, I guess, maybe I can give you some help. the following is parts of my udf.just enjoy it, ^-^. DEFINE_GRID_MOTION(wing, domain, dt, time, dtime) {SET_DEFORMING_THREAD_FLAG(THREAD_T0(tf)); begin_f_loop (f, tf) { f_node_loop (f, tf, n) { v=F_NODE (f, tf, n); if (NODE_POS_NEED_UPDATE (v)) { NODE_POS_UPDATED (v); pos[0]=NODE_X(v); pos[1]=NODE_Y(v); pos[2]=NODE_Z(v); dispz=0.0;// the displacement NODE_Z(v)+=dispz; } } } end_f_loop (f, tf) } good luck.

 January 16, 2004, 04:48 Re: Vibrating / Deforming Wall UDF #3 Qureshi Guest   Posts: n/a Hi CCC, Thanks for posting your part of UDF. I'll be trying it over the weekend. Just a couple of questions. Are doing the case for a 3D case, i.e. the whole wing? I am concerned with a 2D case and may be later on if need be then 3D. Can you elaborate on that? My case is that a wall vibrates in the first mode of vibration. The max amplitude is around .5% of my wall length. The flow moves over the wall. A simple sine wave function with a time period from 0 to Pi/2 gives the curve (just an example) or in other words we can have an equation in terms of x for displacement in y dependent on time t and get the displacement, the first derivative would give velocity and the next acceleration. So how can we go about it? Any ideas or guideline? I am really greatful to you for your assistance. Regards, Qureshi