This completes the problem specification. The Turbulence Kinetic Energy and Dissipation Rate (scroll down to see it) values are set from the prescribed values for the Turbulence Intensity and Hydraulic Diameter at the inlet.Ĭlick Initialize (this is easy to overlook). The Axial Velocity for all cells will be set to 1 m/s, the Radial Velocity to 0 m/s and the Gauge Pressure to 0 Pa. In the Solution Initialization menu that comes up, choose inlet under Compute From. Solution > Solution Initialization > Standard Initialization We'll use an initial guess that is constant over the entire flow domain and equal to the values at the inlet: This will print as well plot the residuals as they are calculated, which you will use to monitor convergence. Select Print to Console and Plot under Options (these are the defaults).
Set the Convergence Criterion to be 1e-06 for all five equations being solved. Notice that Convergence Criterion has to be set for the k and epsilon equations in addition to the three equations in the last tutorial. Solution > Monitors > Residuals, Statistic and Force Monitorsĭouble click on Residuals. We'll iterate the solution until the residual for each equation falls below 1e-6. The residual is a measure of how well the current solution satisfies the discrete form of each governing equation. Recall that Fluent reports a residual for each governing equation being solved. If the second-order scheme doesn't converge, you can try starting the iterations with the first-order scheme and switching to the second-order scheme after some iterations. Second-order discretization generally yields better accuracy while first-order discretization yields more robust convergence. The order of discretization that we just set refers to the convective terms in the equations the discretization of the viscous terms is always second-order accurate in Fluent. We'll use second-order discretization for the momentum equation, as in the laminar pipe flow tutorial, and also for the turbulence kinetic energy equation which is part of the k-epsilon turbulence model.Ĭhange the Discretization for Momentum, Turbulence Kinetic Energy and Turbulence Dissipation Rate equations to Second Order Upwind (if you do not see all of the equations scroll down to see them).
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