hi i am a new user with fluent ( fluent6.1 ) 1. when i tried to compile a UDF, I am getting message: (I had followed the steps given in manual)

Opening library "libudf"...

Error: open_udf_library: The system cannot find the file specified.

Error Object: ()

2. Also, every time I start solution for a problem I get following message:

Error:

FLUENT received fatal signal (ACCESS_VIOLATION)

1. Note exact events leading to error.

2. Save case/data under new name.

3. Exit program and restart to continue.

4. Report error to your distributor.

Error Object: ()

can anybody explain me the the possible errors.

Thanks in advance. ---- MP

Access violation happens when you try to access to a variable which has not been defined yet.

- Gradients are not defined at the first iteration. If you access them, use an if statement like this:

if(!DataValid_P()) return 0;

at the beginning of the function which tries to read a gradient.

- If you use User Defined Memory, make sure to define them in the right number in FLUENT menu. Same for User Defined Scalar.

Hi

ap

1. Make sure that you placed UDF and case file in he same working directory from where you started fluent. If you change the location of udf file, you will get this message. For details, see UDF manual - Errors while compiling udf. 2. Please check all inputs while defining boundary conditions. If you use turbulence intensity (i) & hydraulic gradient as the turbulence specifiaction method, use a lower value of i initially. Then reinitialize the flow domain and give solve.

Hope this may help.

Dear ap and Rahul, thanks for your comments. [ also sorry for my late reply ]

I tried to verify my case in light of your suggestions But, even if i dont use any UDF, i will get the message of ACCESS_VIOLATOIN, for even simpler cases.

Regarding the errors in compilatoin of the UDF, some othere users are also having same trouble particularly with the use of UDF for porosity.

Dear ap,can you please give me some sample UDF which involves the statement viz,

if(!DataValid_P()) return 0;

this could greatly help me.

Thanks for your time.

---MP