Problem Specification — Lesson 1

Turbulent Jet

Additional analysis using Matlab is useful, but not required.

Problem Statement

The laminar and turbulent jets will be set up similarly. The mesh has the dimensions in the above image, and the problem is axisymmetric. Farfield boundary conditions, indicated by lines BC and CD, are specified with gauge pressure 0Pa. Line AD is the centerline (axis). Inlet 1 is on line AB from y = 0 to y = 0.005m and is the jet inflow of 1m/s in the axial direction. Inlet 2 is on line AB as well, from y = 0.005m to y = 0.205m. It has an inlet axial velocity of 0m/s and is also in the axial direction.

In the laminar case, the fluid is air, and should have a density of 1kg/m^3, and viscosity 0.000125 kg/m-s (Re=40). This viscosity will later need to be updated for the turbulent case to provide a higher Reynolds number.

Pope, S.B. Turbulent Flows (2000).