External Flow: Pressure Gradient & Separation

Question 1

what is the pressure gradient for a flat body

Answer 1

dp/dx = 0

Question 2

what causes the pressure gradient for a curved body

Answer 2

acceleration and deceleration of fluid around the body

Question 3

What is the separation point

Answer 3

point at where fluid starts to flow in the reverse direction, where shear stress at the wall, Tw =0

Question 4

Why does the pressure gradient act cause reverse flow after separation

Answer 4

as the boundary layer increases, so does the momentum loss (MdotOut - MdotIn).
The pressure gradient acts against this (-ve Fx) thus reverse fluid flow

Question 5

What is caused by separation

Answer 5

forms a wake of disturbed fluid behind the body

Question 6

how does the pressure of the wake of disturbed fluid vary from the pressure at the start

Answer 6

wake pressure is constant but less

Question 7

why is laminar flow more prone to separation

Answer 7

the velocity increase over the distance of the body is less rapid than that of turbulent thus pressure gradient easily halts the fluid near the surface