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#1 |
Member
Hanye Azimi
Join Date: Oct 2016
Posts: 42
Rep Power: 9 ![]() |
Hi
I'm simulating a flapping airfoil. I mean pitching and heaving by flapping. I've been using this UDF: #include "udf.h" DEFINE_CG_MOTION(airfoil,dt,vel,omega,time,dtime) { Thread *t; face_t f; real w,a,h, pi,fi; pi = 3.14159265; h= 0.5; /*Heave amplitude*/ a = (pi*15)/180; /*pitch amplitude*/ w = 1.168; /*angulat velocity*/ fi =(pi*90)/180 ; /*phase difference*/ /*get the thread pointer for which the motion is defined*/ vel[1] = h*w*cos(w*time); omega[2]=a*w*cos(w*time+fi); } this UDF is defined for airfoil in dynamic mesh zone. Is it the proper user defined function for a flapping motion? Thanks in advance |
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#2 |
Senior Member
Have a nice time!
Join Date: Feb 2016
Location: mech.eng.ahmedmansour@gmail.com
Posts: 291
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Hello dear Hanye, use this :
/**********************************************/ /* flap.c */ /* UDF for specifying a time-varying omega */ /* */ /* Simulates +/- 8 deg flapping with cycle of */ /* of 1 sec. */ /* */ /* Version 13.0 */ /* */ /**********************************************/ #include "udf.h" #define PI 3.141592654 DEFINE_TRANSIENT_PROFILE(speed, time) { real ampl = 2.0*PI/15.0; real freq = 2.*PI; real omega; omega = 2.0*PI*ampl*cos(freq*time); return omega; } |
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#3 |
Member
Hanye Azimi
Join Date: Oct 2016
Posts: 42
Rep Power: 9 ![]() |
@Philip_Morris
I've used this UDF and it is propper for a flapping motion. Airfoil pitches and plunges at the same time. Hope it helps |
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#4 | |
Senior Member
Have a nice time!
Join Date: Feb 2016
Location: mech.eng.ahmedmansour@gmail.com
Posts: 291
Rep Power: 11 ![]() |
Quote:
https://youtu.be/5pltEzl2-J8 Danke! |
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Tags |
flapping motion, fluent, udf |
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