Kinetic Energy

mkress

Hi guys,

 

i would like to compare the kinetic energy of the fluid of different simulations.

In AcuProbe i have only Surface Outputs, nothing like Fluid Output.

 

Have anyone an idea which settings i need for the kinetic energy of the fluid?

 

 

Regards,

Michael

 

 

 

 

 

acupro

You can get some element set averaged quantities if you use a non-zero value for integrated_output_frequency in the ELEMENT_OUTPUT command for your desired fluid volume.  That will give you turbulent kinetic energy.  How do you wish to define - or what do you mean by - 'kinetic energy'?

mkress

Hi acupro,

thank you for your reply!

I simulate the movements of water in a vessel (multiphase, transient). To reduce the fluid movements inside the vessel, i analyze the shape of tank and improve these.

For these studies I want to use the kinetic energy of the fluid. If the amount less the amount of kinetic energy before, I have lowerd the movements inside.

Besides I want compare the results of the kinetic energy from AcuSolve with another CFD-Software, to check the accuracy and differences. Therefore, I need the kinetic energy in the unit Joule or without the mass in m²/s².

 

I´m still a beginner in AcuSolve, perhaps you could show me a screenshot where I implement the command “integrated_output_frequency”. Where could I find ELEMENT_OUTPUT, in the .inp-File?

 

It is possible to get this information’s also from existing AcuSolve results (.log – File)?

 

Thank you very much in advance for your answer!

acupro

If we assume you have an element set named 'flow' - like

 

ELEMENT_SET( 'flow' ) {

...

...

}

 

then

 ELEMENT_OUTPUT( 'sample' ) {  element_set                     = 'flow'  type                            = all  integrated_output_frequency     = 5  integrated_output_time_interval = 0.0  num_user_output                 = 0 }

will give you integrated information for that element set every five time steps.  One of the integrated quantities will be turbulent-kinetic-energy.  But I'm not sure how one would integrate total kinetic energy.  Does you other solver give the equation used for what is reported as kinetic energy?

 

acupro

You may have to write a user function to be used with the ELEMENT_OUTPUT command - to define the element kinetic energy, then the integrated user function quantity will be accessible in the integrated element output data.

mkress

Thank you very much, it works!

 

I have insert

 

'ELEMENT_OUTPUT( 'sample' ) {
element_set                     = 'flow'
type                            = all
integrated_output_frequency     = 5
integrated_output_time_interval = 0.0
num_user_output                 = 0
}'

 

into the AcuSolve input-File and i get the mass_ave_kinetic_energy for my tests. Everything perfect!

 

 

Is there a way, where i do not have to rewrite the input-File?