The non-dimensional fluid temperature profile near the surface of a convectively cooled flat plate is given by \(\frac{{{T_w} - T}}{{{T_w} - {T_\infty }}} = a + b\frac{y}{L} + c{\left( {\frac{y}{L}} \right)^2}\), where y is measured perpendicular to the plate, L is the plate length, and a, b and c are arbitrary constants. Tw and T∞ are wall and ambient temperatures, respectively. If the thermal conductivity of the fluid is k and the wall heat flux is q”, the Nusselt number \(Nu = \frac {q''}{{{T_w} - {T_\infty }}}\frac{L}{k}\) is equal to
b
Differentiating the stated dimensionless temperature profile at y=0 gives a wall-gradient magnitude (Tw−T∞)b/L. Thus h=kb/L and Nu=hL/k=b.
Important Questions from Boundary Layer Theory
Friction drag is generally larger than the pressure drag in _______.
When a fluid flows along a solid boundary, more and more fluid gets retarded in the vicinity of the boundary. This deceleration is accompanied by:
A plate of 500 mm × 200 mm has been placed longitudinally in a stream of an oil which flows with a velocity of 1.0 m/s. The kinematic viscosity of the oil was 0.5 stoke. The thickness of the boundary layer at the trailing edge is _______.
As defined by Prandtl, in convective heat transfer, a thin layer next to the wall where shear stress is confined is called _____.
Thickness of laminar boundary layer on flat plate:
