Time based udf, step gust

April 4, 2005, 07:46

I am looking to create a time based udf. I understand I need to create a c-file, and have already successfully executed a velocity profile program into fluent, however creating a velocity change over time seems to be somewhat different. Also, is there a simple way of graphing the lift and drag results? Any help or example would be much appreciated. Also, is it possible to change the direction of flow in the same function, or would be easier to create two and run them together? Thanks for any help, CJ

April 5, 2005, 11:28

try with a negative value for velocity to reverse flow direction or a reverse pressure drop.

April 5, 2005, 11:29

velcity direction can also be specified. Swarup

April 9, 2005, 08:59

If you want to use a velocity profile in the form:

v = f(t)

you just have to get the current time (in seconds) with the macro CURRENT_TIME.

Best regards, ap

April 4, 2005, 07:46	Time based udf, step gust	#1
CJ Guest Posts: n/a	I am looking to create a time based udf. I understand I need to create a c-file, and have already successfully executed a velocity profile program into fluent, however creating a velocity change over time seems to be somewhat different. Also, is there a simple way of graphing the lift and drag results? Any help or example would be much appreciated. Also, is it possible to change the direction of flow in the same function, or would be easier to create two and run them together? Thanks for any help, CJ

April 5, 2005, 11:28	Re: Time based udf, step gust	#2
swarup Guest Posts: n/a	try with a negative value for velocity to reverse flow direction or a reverse pressure drop.

April 5, 2005, 11:29	Re: Time based udf, step gust	#3
swarup Guest Posts: n/a	velcity direction can also be specified. Swarup

April 9, 2005, 08:59	Re: Time based udf, step gust	#4
ap Guest Posts: n/a	If you want to use a velocity profile in the form: v = f(t) you just have to get the current time (in seconds) with the macro CURRENT_TIME. Best regards, ap

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