Hello Fellow Stressers!!

How would you consider the direction of reaction load in a 90 deg. elbow? Is it one direction along the direction of flow Fx (say x is the flow direction)? or FR= SQRT (Fx^2 + Fz^2) (z & x are the components or resultant Force FR)?

Warm Regards,

I suggest Fx and Fz. If you use FR, you will be constantly checking (and re-checking) the equation SQRT(Fx^2 = Fz^2) to verify the value of FR.

Thanks Richard.

To make more clear my question, please find below case 1 and case 2.

Case 1: The resultant force acting on the elbow is applied only in one direction (Fx) at the flow direction. Fx= rho*A*V^2

Case 2: The resultant force acting on the elbow is resolved and applied into two components (orthogonal to each other) (Fx and Fz), where the components Fx and Fz is a function of the angle of the elbow.

Which of the two practice is more realistic?

Warm Regards,

I suggest "case 2". This is much easier to verify and understand.

If you use "case 1", the direction of application would be the direction that bisects the elbow.

Thanks Richard.

Fr = rho a v squared, and is oriented at the half-long-angle.

Fx = Fr cos((360-theta)/2)
Fy = Fr sin((360-theta)/2)

If your angle isn't 90, then these 2 forces are not equal.