Learning Forum

[Najib.Sarbini]

Im really new to ansys fluent and i need to figure how to make pulsating flow on fluet,

my case study is a 2d rectangular tank with one crossflow and one pulsating jet at the bottom of the tank.

[Keyur Kanade]

Do you want to do it in AIM or in Fluent?

Regards,

Keyur

[Najib.Sarbini]

Fluent

[Keyur Kanade]

Moving to Fluid Dynamics category. 

Regards,

Keyur

[Najib.Sarbini]

Alright thank you

[Rob]

At present you'll need a User Defined Function or transient profile to do the pulsed flow.  The former is covered in the Customisation Manual, the latter in the User Guide. 

[DrAmine]

I want to add to what rwoolhou already wrote: Is the pulsation for an inflow boundary?

[Najib.Sarbini]

Im not sure what you meant, but the pulsation comes from the ejected jet.

Thank you in advance

[Karthik R]

Hello
Rwoolhou and abenhadj are suggesting that you use ‘User Defined Functions (UDFs)’ or ‘Profiles’ in Fluent to create a pulsating jet. UDFs are codes based on some Fluent macros where you can write an analytical expression for your velocity as a function of time. This UDFs will be compiled, loaded, and hooked to your Fluent case as a boundary condition. You can find more information about this UDF in the Fluent customization manual.

About ‘profiles’ - profiles are external files which contain information about the velocity of your pulsating jet as a function of time. These files can directly be read into Fluent. You will need to create these files in a specific format, which can be found in the Fluent Users Guide.

I hope this clarifies both their answers.

Best Karthik

[DrAmine]

To clarify my question: Is the velocity you provide at your inlet constant or does undergo a pulsating profile.

 

If the velocity at the inlet is not really pulsating (say behaving as sin profile) which  I think actually, then the jet pulsation itself in the core will be due to external destabilizing forces and other stabilizing forces (surface tension forces if you are injecting liquid into a gas and viscous forces)