HI,

I would try to simulate a simple problem before a complecated situation. I saw UDF manual provided by FLUENT.INC., but couldn't understand. My simple situation is that upper wall(rigid body) is moving up and down with a sinusoidal function in a parallel plate. Inlet velocity is given uniformly. No-slip condition is given in lower wall. I found out that there are three types of dynamic mesh define macros,ie DEFINE_CG_MOTION, DEFINE_GEOM, and DEFINE_GRID_MOTION.

What type of macros shoud I use for solving the problem?

The upper wall is moving as follows: r=r_mean + r_amp*sin(omega*time) r_mean = mean position r_amp= amplitude of postion omega=angula velocity(=1)

If you can knw how to set up udf, could you please write it here for me? Your help would be greatly appreciated.

Thanks again

Hi SUKI I'm having the same pb writing UDF for modeling oscillating and rotating NACA-foil movement, which cordinates are: X= R*(1.7*omega*t+sin(omega*t)). Y=R*cos(omega*t). where: R=radius=distance of pivot point (1/3 chord length) to centre of rotation. omega= angular velocity. my first pb is that I didn't get yet the licence and help files for Duynamic mesh, thus I don't know how strong is this utility. my second pb is that I wonder if I can't do that simply with moving wall option with specifying my wall (NACA)velocity coordinates!!!!! at last, what about the sliding mesh option? have you ever tried it? ******************************

HI, caloggero

Is the dynamic mesh different in idea to sliding mesh? Under my problem, I have to use the first.

thanks.

Hi

You can get acccess to Fluent information in the following address

http://www.psc.edu/general/software/...f/main_pre.htm

perhaps it can help you until you get the accest to fluent support.

Regards

Alex

thanx Alex, this is really helpful !