Exercises

Laminar Jet

1. Evaluate and plot the spreading rate of the jet, S = dR(x)(1/2)/dx where R(x)(1/2) is the half width of the laminar jet, computed in the Laminar Jet - Results section. For a jet that spreads linearly, the spreading rate will be constant, although there will be a steep differential and non constant spreading as the jet is initially exposed to the environment.
2. Evaluate and plot the local Reynolds number of the flow, given by R = (U_center)*R(x)(1/2)/ν. The average local Reynolds number should be independent of x and be approximately 40.

Turbulent Jet

1. Examine the self-similarity of the profiles of the turbulent kinetic energy k, and turbulent dissipation ε. The scaling factor for the turbulent kinetic energy profile should be 1/(U_center)^2, because kinetic energy depends on the square of velocity. The scaling factor for the turbulent dissipation should be R(x)(1/2)/(U_center)^3, where R(x)(1/2) is the jet half width. 

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