Question

Indicate the correct statement about the effect of Reynolds number on the character of the flow over an object.

If Reynolds number is high enough the effect of viscosity is negligible and the fluid flows over the plate without sticking to the surface.

If Reynolds number increases the extent of the region around the object that is affected by viscosity decreases.

If Reynolds number is low enough the effect of viscosity is so high that there is a region near the plate where the fluid is stationary.

If Reynolds number increases the size of the region around the object that is affected by viscosity increases.

Answer 1

If Reynolds number increases the extent of the region around the object that is affected by viscosity decreases.

Step-by-step explanation:

Reynolds number is an important dimensionless parameter in fluid mechanics.

It is calculated as;

`R_e__N} = (\rho vd)/(\mu)`

where;

ρ is density

v is velocity

d is diameter

μ is viscosity

All these parameters are important in calculating Reynolds number and understanding of fluid flow over an object.

In aerodynamics, the higher the Reynolds number, the lesser the viscosity plays a role in the flow around the airfoil. As Reynolds number increases, the boundary layer gets thinner, which results in a lower drag. Or simply put, if Reynolds number increases the extent of the region around the object that is affected by viscosity decreases.