## Fluids

Topics relate to Fluent, CFX, Turbogrid and more

#### UDF 3D Rotation for Fluid in concentric sphere

• AndyHor
Subscriber

Hi everyone,

I am first time user to UDF, and using ansys 2016.

I am trying to put expressions for a 3D , 1/8 concentric sphere, and the fluid is driven by lower surface to oscillate with respect to z-axis. Two pictures is shown in below for better view.

In 2019 version, i can put the boundary conditions as expression as sin(t/1)*1[rad/s] for the lower oscillating surface.

If I want to write in UDF, can I write in this way ? Please advise.

/**********************************************************************

oscillatingwall.c

UDF for specifying a transient simple harmonic motion

***********************************************************************/

#include "udf.h"

#define angular_freq 1

DEFINE_GRID_MOTION(inneroscillatingwall, dt, cg_vel, cg_omega, time, dtime)

{

Thread*t; /*is the pointer to the structure that store*/

real omega;

/* reset velocities */

NV_S (vel, =, 0.0);

NV_S (omega, =, 0.0);

omega = sin(angular_freq*time); /*rotional speed about axis*/

cg_vel[0] = 0.0; /*x y z translation*/

cg_vel[1] = 0.0;

cg_vel[2] = 0.0;

cg_omega[0]=0.0;  /* x y z rotational axis*/

cg_omega[1]=0.0;

cg_omega[2]=omega;

}

• AndyHor
Subscriber

I have tried several methods, and amended some code, this is what I currently facing, could anyone please help ?

#include "udf.h"

#define angular_freq 1.0

DEFINE_CG_MOTION(inneroscillatingwall, dt, cg_vel, cg_omega, time, dtime)

{

real omega;

omega = sin(angular_freq*time); /*rotional speed about axis*/

cg_vel[0] = 0.0; /*x y z translation*/

cg_vel[1] = 0.0;

cg_vel[2] = 0.0;

cg_omega[0]=0.0; /* x y z rotational axis*/

cg_omega[1]=0.0;

cg_omega[2]=omega;

}

/*When I press build button, it gives */

Setting Post Processing and Surfaces information ... Done.

Copied C:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluent/C:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentUDF oscillating.c to libudfsrc

Creating user_nt.udf file for 3ddp ...

(system "copy "C:PROGRA~1ANSYSI~1v170fluent"fluent17.0.0srcudfmakefile_nt.udf "libudfwin643ddpmakefile" ")

1 file(s) copied.

(chdir "libudf")(chdir "win643ddp")'nmake' is not recognized as an internal or external command,

operable program or batch file.

Done.

/*When I press load button, it gives*/

Opening library "C:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentC:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentlibudf"...RPC RCX_SC_SET_ERR_MSG failed: RPC: Can't encode arguments

Error: The UDF library you are trying to load (C:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentlibudf) is not compiled for 3ddp on the current platform (win64).

The system cannot find the file specified.

C:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentC:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentlibudfwin643ddplibudf.dll

Error: The UDF library you are trying to load (C:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentlibudf) is not compiled for 3ddp on the current platform (win64).nnThe system cannot find the file specified.

nnC:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentC:UsersDell T7600DesktopChee Hao AnsysHip Gap_filesdp0FFFFluentlibudfwin643ddplibudf.dll

Error Object: #f

/*And then I restart Ansys, it somehow have the UDF file, when I load to the boundary, and press ok, it gives */

Error: received a fatal signal (Segmentation fault).

Error: received a fatal signal (Segmentation fault).

Error Object: #f