Learning Forum

[zdfrankman]

I am modeling a 5mm by 1mm by 50mm channel filled with fluid under laminar flow with a 2400Pa pressure differential. Analytically, it should produce a maximum velocity of 6m/s. However, ANSYS Fluent produces a maximum velocity of ~2m/s with the same inputs.

I am unsure why, but my velocity is only one third of the predicted velocity from Poiseuille equation for a rectangular channel.

All input parameters (viscosity, pressure differential, channel height, etc) are the same. Therefore I hypothesize that the disparity in result magnitude originates from an improper meshing or simulation setup.

What did I do wrong, and how can I use ANSYS fluent to provide more analytically accurate solutions?

[DrAmine]

Analytical Solution is assuming a fully developed flow. For laminar flow for example you require at least 100D.l Moreover for duct the velocity profile will be bit different. Please try to make your near wall mesh better and assess a uniform mesh along the streamwise direction!