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Repeat Example 6.1, but with the somewhat more realistic assumption that the flow is similar to a free vortex (irrotational) profile, Vθ = c/r (where c is a constant), as shown in Fig. P6.25. In doing so, prove that the flow rate is given by
and w is the depth of the bend.
P6.25
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Fox and McDonald's Introduction to Fluid Mechanics
- Q.4 A steady, uniform-density, 2-D flow is to be calculated on the square grid shown below. The boundary velocities are given as; v₁ =30, V = 40,uc=100, u = 50, u = 200, u, = 210, V = 0 and v₁ = 20. Among these numbers, there is some doubt about correctness of the value of u,. If all other numbers are correct, what should be the correct value of u,? The internal velocities are governed by simplified momentum equations given by: up = 70+0.5 (P₁-P₂) u, = 10 +0.7 (P3-P4) V =30+0.5(P3-P₁) VG =18+0.8(P₁-P₂) Write discretized continuity equation for each control volume. Derive the discretization equation for pressure by substituting from momentum equations, following SIMPLER calculation procedure. Solve the pressure equations to obtain P₁, P2, P3 and P₁. Hence obtain values of up, u, V and VGarrow_forwardQ.4 A steady, uniform-density, 2-D flow is to be calculated on the square grid shown below. The boundary velocities are given as; v₁ = 30, V = 40,uc=100, u = 50, u = 200, u, = 210, v = 0 and v₁ = 20. Among these numbers, there is some doubt about correctness of the value of u,. If all other numbers are correct, what should be the correct value of u,? The internal velocities are governed by simplified momentum equations given by: up=70+0.5(P₁-P₂) u, = 10+0.7 (P3-P4) V=30+0.5(P₁-P₁) V=18+0.8(P₁-P₂) Write discretized continuity equation for each control volume. Derive the discretization equation for pressure by substituting from momentum equations, following SIMPLER calculation procedure. Solve the pressure equations to obtain P₁, P2, P3 and p₁. Hence obtain values ofu,, U₁, V and V6.arrow_forward6.52 The motion of a liquid in an open tank is that of a combined vortex consisting of a forced vortex for 0 2 ft. The velocity profile and the corresponding shape of the free surface are shown in Fig. P6.52. The free surface at the cen- ter of the tank is a depth h below the free surface at r = o. Deter- mine the value of h. Note that h = hforeed + hiees where hforeed and hfree are the corresponding depths for the forced vortex and the free vortex, respectively. (See Section 2.12.2 for further discussion regarding the forced vortex.) 10 Ve, ft/s r, ft 2 2 r, ft h IFIGURE P6.52arrow_forward
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- 3.4 Consider a steady, incompressible, 2D velocity field for motion parallel to the X-axis with constant shear. The shear rate is du/dy Ay. Obtain an expression for the velocity field V. Calculate the rate of rotation. Evaluate the stream function %3D for this flow field. Ay Ay + В і, о, Ay + By+ C 6. Ans: V= 2arrow_forwardQ.5 The velocity components in x and y direction 2 are given by u = Axy° - xy; v = > ху; v — ху = xy² – 3/4 .4 y*. The value of A for a possible flow field involving an incompressible fluid is: A -3/4 В 3 C 4/3 D -4/3arrow_forwardUsing the figure depicted below, perform the following: (a) Calculate the minimum height h at which cavitation occurs. Indicate on the figure where the cavitation occurs. (b) Calculate the volume flowrate (in m³/s) if h = 25 cm. Be sure to state all assumptions. Note that section 2 opens to atmosphere. D1 = 5 cm h D2 = 10 cm Free Jet (1) 2 Water at 20°Carrow_forward
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