# Finding out Shear rate of a bent pipe which has different bend radius values

Tags:
1. Mar 4, 2016

### Baybora

which has different radiuses at both end. Its actually two pipes merging after the entrance going straight and somewhere close to middle of the pipe it's bent 90°.

So for simple pipes it's
=4*Q
π*r^3

But what for the pipe I mentioned? Is there any way to solve that or at least minimize the error?

2. Mar 4, 2016

### Staff: Mentor

Do you really think we can figure out the geometry of the system from your description?

3. Mar 11, 2016

### Baybora

here is the shape I was talking about. Hope this helps

4. Mar 11, 2016

### Baybora

bump

5. Mar 11, 2016

### Staff: Mentor

The shear rate at the wall varies with position around the circumference for the curved sections, so there is no one value of the shear rate that you can assign to the flow. However, if the radius of curvature of the bends is large compared to diameter of the pipe, a good approximation is to use the shear rate as if the pipe were not curved.

6. Mar 11, 2016

### Baybora

It looks like the curve Radius is 50 mm and the pipe diameter before the curve is 40 mm. Is there any specific ratio to determine if the result of fixed shear rate could be negligible?

7. Mar 11, 2016

### Staff: Mentor

I would go by 10:1

8. Mar 18, 2016

### Baybora

I couldnt find anything regarding to calculation of a bent pipe. Is there even a way other than experimenting?

9. Mar 18, 2016

### Staff: Mentor

You should be able to find Laminar Flow in curved Pipe or Toroidal flow