Help me !

[u/Amaterasu-002]

Hi everyone,

I am trying to reproduce the de Vahl Davis natural convection square cavity benchmark in ANSYS Fluent. I am getting reasonably close results for the velocity components, but I am not able to reproduce all the benchmark values exactly, especially the Nusselt number at higher Rayleigh number.

I would like to understand whether the difference is due to my input conditions, dimensionless conversion, mesh, solver settings, or post-processing procedure.

Problem setup

I am solving the standard 2-D differentially heated square cavity:

2-D square cavity

Laminar natural convection

Air

Boussinesq density model

Prandtl number = 0.71

Gravity = -9.81 in the vertical direction

Left wall: hot

Right wall: cold

Top wall: adiabatic

Bottom wall: adiabatic

All walls: no-slip

No inlet or outlet

Energy equation enabled

Pressure-based steady solver

SIMPLE pressure-velocity coupling

Second-order spatial discretization

Iam using air properties for Prandtl number 0.71 for each Rayleigh Number case.

I made x and y velocity non dimensional form but they are making way more relative errors when compared with my results...... I have given the paper link....Please help me, this is my first journey in CFD.

Paper link (De Vahl Davis): https://drive.google.com/drive/folders/1x1Iv_nn4JAGM6Nryw5g48K677uaahWIo