Learning Forum

[btingthewind]

Dear you,

Now I am doing a steady state simulation in Fluent with pressure based solver.

Boundary condition:

Velocity inlet (Velocity 10 m/s, Reynolds number 4000), pressure outlet, and other sides are periodic and symmerty.

Mesh quality:

Minimum orthogonoal 0.2.

Turbulence model:

RNG ke with enhanced wall treatment.

Pressure drop is defined as:

Static pressure of (the inlet - outlet).

My question is:

Why the pressure drop fluctates in a sinoidal pattern with in a range of 2 Pa, even the residuals of continuity and so on below 1e-5?

BEST REGARDS

[Murari Iyengar]

Hi btingthewind This could happen due to a couple of reasons.
High mesh skewness/aspect ratio: Please look through Chapter 22: Improving the Mesh (ansys.com).
Incorrect model: Maybe K-e is not the correct model for your simulation. Try other turbulence models. Also, the Re is 4000 which indicates a mix of laminar and turbulent flow (I'm assuming you are doing internal flow). This could also be a reason for fluctuating residuals since the flow might not be steady.

[Rob]

Please can you post some images? Depending on the pressure 2Pa could be near enough zero change or huge.

[btingthewind]

Many thanks to you!!

[btingthewind]

Many thanks to you!!