<p> FLOWLAB SOLUTION</p><p>9.114 Use the cylinder template in FlowLab to investigate how the viscous and 2 inviscid surface pressure coefficient distributions, Cp = p/(ρU /2), differ for flow past a circular cylinder. For the viscous case, choose a Reynolds number between Re = 10 and 40 (so the steady solver can be used) by selecting appropriate values for the cylinder radius, free stream velocity, density, and viscosity. Use the same values, other than viscosity, for the inviscid case. For each case, plot the pressure coefficient distribution as a function of location on the surface of the cylinder and explain the differences in the two results.</p><p>Problem Setup</p><p>The default cylinder radius was used for this problem:</p><p>Given the Reynolds number range, the Laminar condition was selected for the viscous simulation. For Re < 40, it is advised to use the steady flow solver, as shown below. For this simulation, the Boundary Condition and Materials were altered to give Re = 20.</p><p>The Boundary Condition and Materials windows are shown below:</p><p>For the inviscid portion of the problem, the Inviscid button was selected under the Viscous Conditions, with the flow solver still set to Steady. For both simulations, the medium grid resolution was selected for the grid around the cylinder, which is shown in the following figure.</p><p>A close-up of the grid region surrounding the cylinder is shown in the figure below. Answer</p><p>For both simulations, the default convergence limit of 1x10-6 was used and the number of iterations was set to 1000 (default). A sample of the convergence history for the viscous flow case is shown in the following figure.</p><p>Viscous The convergence history for the inviscid case is shown below.</p><p>Inviscid</p><p>Note: had to increase default number of iterations for the inviscid case. After not converging in 1000 iterations, the Iterations value was increased to 2000 and the Restart box selected. Then pressing the Iterate button, FlowLab will start where it left off.</p><p>For each simulation, viscous and inviscid, the students are required to plot the surface pressure coefficient distribution over the cylinder and make a comparison of the plots. These plots are shown below for the viscous and inviscid cases, respectively.</p><p>Viscous Inviscid Both plots show the same trends as Figure 9.17c in the text. The students should present discussion on why the pressure coefficient plots differ, as outlined in Sec. 9.2.6.</p><p>Additional Material</p><p>Though not required in the problem statement, the following additional material helps support the differences between the viscous and inviscid flows past a circular cylinder.</p><p>The following plots show the streamlines and velocity contours for both the viscous case and the inviscid case. The streamline plot for the viscous flow agrees with Fig. 9.21b at the given Reynolds number. Flow separation can be seen for the viscous case, but not for the inviscid flow.</p><p>Viscous Inviscid</p>