FLUENTUDF+"TIME" VARIABLE NAME IN COUP+EXP SOLVER?

April 14, 2002, 12:45

Dear Madam, Sir ;

I need to find the name of the TIME variable that is used in the original C code of Fluent for unsteady coupled explicit solver.I 'll use it to write my own UDF which computes a time dependent inlet boundary velocity.I have to save the time values ,so that variable is critical. I've examined the udf tutorials and lots of messages in this group but couldn't find it. I'll be happy if anybody informs me about this subject. I'm looking forward to your messages, because the deadline for the project is on the first week of May. Thanks...

Taner.

April 14, 2002, 22:14

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<html> <head>

<title>My Web Site Title</title> </head> <meta name="Description" content="A Short but sharp description of website or web page for search engines"> <meta name="Keywords" content="A list of keywords users may type in a search engine to find website or page"> <meta name="Generator" content="WebSoftware HotHTML 2001 Professional Edition"> <body bgcolor="#FFFFFF" text="#000000" link="#804040" vlink="#008080" alink="#004080">

Hi, The following is a sample code:

The C function (sinusoidal-v.c) that will be used to compute this velocity is shown below.

#include "udf.h"

DEFINE_PROFILE(inlet_xv_sinusoidal, thread, nv)

{ face_t f;
<font color="#FF0000">
real flow_time = RP_Get_Real("flow-time"); /*!!! Maybe this is what you want ... */
</font>begin_f_loop (f,thread)
{

F_PROFILE(f,thread,nv) = 20. + 5.*sin(10.*flow_time);

} end_f_loop (f,thread) }

The function that is defined is named inlet_xv_sinusoidal. A floating point variable is created for the time, flow_time.

Before you can compile this UDF, you must specify an unsteady flow calculation.

<font color="#0000FF">
Good Luck!
</font>

</body> </html>

April 15, 2002, 06:19

Hi Johnix! Thank you for your interest, but I want to save the time values for Coupled Explicit solver. I've examined the tutorials before and tried to save them using "flow-time" variable but it didn't work out.I think that is something different for Coupled solver. Sincerely...

Taner BALKAN Istanbul

April 15, 2002, 10:16

Hi, Taner

In my opinion, whether the time value is savable doesn't depend on what solver(ex/im) you choose.

o you have to choose "Unsteady solver"

o In Iterate dialogbox, set "Time step size", "Number of time step" and "Max Iterations per time step" correctly ...

I tyied, and it worked well, suppose I have understood your question...

April 16, 2002, 05:58

Dear Johnix ! In some udf tutorials time variable is written as "flow_time". After I have examined your first message again, I became aware of where the problem is. "flow-time" is the right usage

Thank you for your interest again...

Sincerely Taner

April 14, 2002, 12:45	FLUENTUDF+"TIME" VARIABLE NAME IN COUP+EXP SOLVER?	#1
Taner Guest Posts: n/a	Dear Madam, Sir ; I need to find the name of the TIME variable that is used in the original C code of Fluent for unsteady coupled explicit solver.I 'll use it to write my own UDF which computes a time dependent inlet boundary velocity.I have to save the time values ,so that variable is critical. I've examined the udf tutorials and lots of messages in this group but couldn't find it. I'll be happy if anybody informs me about this subject. I'm looking forward to your messages, because the deadline for the project is on the first week of May. Thanks... Taner.

April 14, 2002, 22:14	This is an example in Fluent user's guide ...	#2
Johnix Guest Posts: n/a	<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.0 Transitional//EN' > <html> <head> <title>My Web Site Title</title> </head> <meta name="Description" content="A Short but sharp description of website or web page for search engines"> <meta name="Keywords" content="A list of keywords users may type in a search engine to find website or page"> <meta name="Generator" content="WebSoftware HotHTML 2001 Professional Edition"> <body bgcolor="#FFFFFF" text="#000000" link="#804040" vlink="#008080" alink="#004080"> Hi, The following is a sample code: The C function (sinusoidal-v.c) that will be used to compute this velocity is shown below. #include "udf.h" DEFINE_PROFILE(inlet_xv_sinusoidal, thread, nv) { face_t f; <font color="#FF0000"> real flow_time = RP_Get_Real("flow-time"); /!!! Maybe this is what you want ... / </font>begin_f_loop (f,thread) { F_PROFILE(f,thread,nv) = 20. + 5.sin(10.flow_time); } end_f_loop (f,thread) } The function that is defined is named inlet_xv_sinusoidal. A floating point variable is created for the time, flow_time. Before you can compile this UDF, you must specify an unsteady flow calculation. <font color="#0000FF"> Good Luck! </font> </body> </html>

April 15, 2002, 06:19	Re: This is an example in Fluent user's guide ...	#3
Taner Guest Posts: n/a	Hi Johnix! Thank you for your interest, but I want to save the time values for Coupled Explicit solver. I've examined the tutorials before and tried to save them using "flow-time" variable but it didn't work out.I think that is something different for Coupled solver. Sincerely... Taner BALKAN Istanbul

April 15, 2002, 10:16	Re: This is an example in Fluent user's guide ...	#4
Johnix Guest Posts: n/a	Hi, Taner In my opinion, whether the time value is savable doesn't depend on what solver(ex/im) you choose. o you have to choose "Unsteady solver" o In Iterate dialogbox, set "Time step size", "Number of time step" and "Max Iterations per time step" correctly ... I tyied, and it worked well, suppose I have understood your question...

April 16, 2002, 05:58	Re: This is an example in Fluent user's guide ...	#5
Taner Guest Posts: n/a	Dear Johnix ! In some udf tutorials time variable is written as "flow_time". After I have examined your first message again, I became aware of where the problem is. "flow-time" is the right usage Thank you for your interest again... Sincerely Taner

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