For an external flow over a tube, the critical reynolds number is 2300 t f radiation heat transfer can take place irrespective of the presence of a medium. a) true b) false

Acompressor receives the shaft work to decrease the pressure of the fluid. a)- true b)- false

Air flows over a heated plate àt a velocity of 50m/s. the local skin factor coefficient at a point on a plate is 0.004. estimate the local heat transfer coefficient at this point.the following property data for air are given: density = 0.88kg/m3 , viscosity 2.286 x 10 ^-5 kgm/s , k = 0.035w/mk ,cp = 1.001kj/kgk. use colburn reynolds analogy.

The sum of the normal stresses does not change as the stress state rotates through an angle. a)-trune b)- false