Static pressure P is measured at two locations along the wall of a laminar boundary layer (Fig. 10-104). The measured pressures are P1and P2distance between the taps is small compared to the characteristic body dimension
b
FIGURE P10-104
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Fluid Mechanics: Fundamentals and Applications
- Two infinite plates a distance h apart are parallel to the xzplane with the upper plate moving at speed V, as inFig. There is a fluid of viscosity μ and constant pressurebetween the plates. Neglecting gravity and assumingincompressible turbulent flow u(y) between the plates, usethe logarithmic law and appropriate boundary conditions toderive a formula for dimensionless wall shear stress versusdimensionless plate velocity. Sketch a typical shape of theprofile u(y).arrow_forwardA curved blood vessel has an internal diameter ? = 5 mm and a radius of curvature of ?? = 17 mm. Blood has a density of ρ = 1060 kg/m3 and a viscosity of 3.5 cP, and travels at an average velocity of ? = 1 m/s. a) Comment on the nature of the flow with reference to relevant non-dimensional groups. b) Can the flow be modelled using the Hagen-Poisseuile equation? If not, explain what specific assumptions are invalid. c) The viscosity of blood is measured and is shown in Figure Q2. Consider two long straight blood vessels with steady flow. The diameter of the first vessel is 5 mm and the average velocity is 6 cm/s. The internal diameter of the second vessel is 2.2 mm and the average velocity is 50 cm/s. Which vessel would you expect the Hagen-Poisseiulle equation to be more accurate in? Explain your answer (1-2 sentences).arrow_forwardBy using the expression for the shear stress derived in class (and in BSL), show that the shear force on asphere spinning at a constant angular velocity in a Stokes’ flow, is zero.This means that a neutrally buoyant sphere (weight equal buoyancy force) that is made to spin in aStokes’ flow, will neither rise nor fall, nor translate in any preferential direction in the (x-y) plane. expressions for velocity are: v_r (r,θ)= U_∞ [1-3R/2r+R^3/(2r^3 )] cosθ v_θ (r,θ)= -U_∞ [1-3R/4r-R^3/(4r^3 )] sinθ Where v_r and v_θ are the radial and angle velocity, U_∞ is the velocity of fluid coming to sphere which very faar away from the sphere. And R is the radius of sphere.arrow_forward
- A long wire of length L to be coated moves at a velocity V0 through a long cylindrical diefilled with an incompressible fluid (density ρ and kinematic viscosity μ). Using cylindricalco-ordinates (r-z) and assuming that pressure is uniform (i.e. dp/dz = 0 and dp/dr = 0).Assume that the flow is steady, laminar and fully developed (neglect any end effects). Clearly4 show all steps, starting from the Navier-Stokes equations, simplifying them, specify properboundary conditions.(a) Find velocity vz as a function of radius inside the die. Use continuity, and momentumequations and clearly show which terms vanish (and why).(b) Also find the force F required to pull the wire in terms of the given known parameterssuch as V0, L, μ, R1, R2 etc.arrow_forwardFor each statement, choose whether the statement is true or false, and discuss your answer briefly. (a) The velocity potential function can be defined for threedimensional flows. (b) The vorticity must be zero in order for the stream function to be defined. (c) The vorticity must be zero in order for the velocity potential function to be defined. (d) The stream function can be defined only for two-dimensional flow fields.arrow_forwardA- Womersley number (a) of a human aorta is 20 and for the rabbit aorta is 17, the blood density is approximately the same across the species. The values of viscosity were 0.0035 Ns/m² for the human and 0.0040 Ns/m² for the rabbit. The diameter of the aorta is 2.0 cm for the man, and 0.7 cm for the rabbit, estimate the heart rate beats per minute (bpm) for both speciesarrow_forward
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- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning