Question

Vid 15. One expression for the Reynolds number is Rem a. Since the Reynolds number must be dimensionless, what are the units of the v term in the denominator? b. Does the v term represent the kinematic or dynamic viscosity? c. Find the coefficient of drag of a sphere (d=0.5m) if cold air, with a density of 1.29 kg/m' is blowing on it with a velocity of 35 m/s and a dynamic viscosity of 1.72d0N s/m?.

Answer 1

Answer :

a) unit of v term = m^{​​​​​​2}​​​/s

b) v terms is kinematic viscosity

c) coefficient of drag = 4.3*10^{​​​​​​-3}

Explanation :

Rea c a) Units of こ morf 6) Given data. Reynoldis number, Vod V Solution: bere, Voy average velocity in (m/s) d Characteristie dimension in (m) kinematic viscosity in (m/ (or styoles) ) in (mols cors styoles) =) dynami visuals density V termi Vo mkim m/ m/ m% = 1 (dimensionley) Su, unt of kinematic discosity ) is V tem represents - Kinematic viscosity ģ P= 1.29 byloms : de 0.6 m; Velocity (Da 35 ml Ma 1.79x lot Nstma evel Reynolds number Rea 1.29X35 x 0.5 м 1.72xcot Rec 1312500 The flow is turbulent here (1349500- 20008) 0.072 0.072 Su coefficient of drag, at (Reja B12500) Y5 Co= 4.Bxc6-3 Am! Cefficient of deeg = 4.8*20-3