Question 31. The zone or thin layer wherein the temperature field exists is called the

Question 32. The velocity profile of the hydrodynamic boundary layer is dependent upon

Question 33. Which is true for two dimensional boundary layer?

Question 34. The assumptions for thermal boundary layer are
(i) Steady compressible flow
(ii) Negligible body forces, viscous heating and conduction in the flow direction
(iii) Constant fluid properties evaluated at the film temperature
Identify the correct option

Question 35. The differential energy equation for flow past a flat plate is given by

Question 36. The relationship between the thermal and hydrodynamic boundary layer thickness is governed by the

Question 37. A small thermo-couple is positioned in a thermal boundary layer near a flat plate past which water flows at 30 degree Celsius and 0.15 m/s. The plate is heated to a surface temperature of 50 degree Celsius and at the location of the probe, the thickness is 15 mm. The probe is well-represented by
t – t S/t INFINITY – t S = 1.5 (y/δ) – 0.5 (y/δ)³
Determine the heat transfer coefficient

Question 38. Ambient air at 20 degree Celsius flows past a flat plate with a sharp leading edge at 3 m/s. The plate is heated uniformly throughout its entire length and is maintained at a surface temperature of 40 degree Celsius. Calculate the thickness of the thermal boundary layer. Assume that transition occurs at a critical Reynolds number of 500000

Question 39. Temperature and velocity profiles are identical when the dimensionless Prandtl number is

Question 40. The average drag coefficient for turbulent boundary layer flow past a thin plate is given by
Cf = 0.455/ (log10 Rel)^2.58
Where R el is the Reynolds number based on plate length. A plate 50 cm wide and 5 m long is kept parallel to the flow of water with free stream velocity 3 m/s. Calculate the drag force on both sides of the plate. For water, kinematic viscosity = 0.01 stokes