# unsteady Boundary Condition ( user defined function)

 Register Blogs Members List Search Today's Posts Mark Forums Read

 June 1, 2022, 07:28 unsteady Boundary Condition ( user defined function) #1 New Member   Join Date: Apr 2022 Posts: 9 Rep Power: 3 Hey Guys, I want to simulate a fluctuating flow, that flow through the Turbine ( just NGV). A sine function can describe the fluctuating pressure in the inlet good. So I want to use a unsteady Boundary condition at the inlet that change with time. But I find nowher the option to use a user defined function. I just can click at the absolute total pressure, change the parameter from constant to function and upload a graph. The sine function has the simple form: p = Amplitude*sine*(2*pi*frequence*time). greetings Hussein

 June 7, 2022, 09:56 #2 Senior Member   Colinda Join Date: May 2012 Location: Brussels Posts: 149 Rep Power: 13 Hi Hussein, Which environment are you using? Omnis or Fine? Which version? Best regards, Colinda

June 7, 2022, 10:31
#3
New Member

Join Date: Apr 2022
Posts: 9
Rep Power: 3
Quote:
 Originally Posted by colinda1 Hi Hussein, Which environment are you using? Omnis or Fine? Which version? Best regards, Colinda

Hi Colinda,
iam using Omnis 5.2, the problem has solved. I Found the feature thx. There is another issue, in the manual/Omnis Environment/ Profil manager/Standard CSV Format/ the theta, that is defined there, is it the azimuthal angle ?
And since I have a fluctuating flow I have a variation in the velocity angle within a range of ±40 degree. Where can I define these angle ? Because for example in the Inlet/subsonic/cylindrical/total quantities imposed/angle from axial direction or relative angle from axial direction and more, maybe I can define the velocity angle here ? I have attached a picture, there is alpha ( velocity angle) applied over the azimuthal angle. greetings Hussein
Attached Images
 2.png (59.6 KB, 9 views)

 June 9, 2022, 05:53 #4 New Member   Join Date: Apr 2022 Posts: 9 Rep Power: 3 problem has already solved colinda1 likes this.