How do I solve the colbrooke equation by iteration in Excel?

[Steve M.]

I want to program excel to check whether fluid flow is laminar, transitional,
or turbulent and use corresponding equations to solve for friction.

Laminar (re<2300) - friction = Re/64
Transitional (2300<re<4000) - friction use Churcill equation
Turbulent (re>4000) - friction use colebrooke iterative equation

I have the flow type listed in one column and I would like the corresponding
friction factor to be listed in the adjacent column.

--Steve

 

[Joel]

I would use a UDF. Use the mode either 1 or 2 to return the value or the type

Function Fluid_Flow(mode As Integer, re As Single)

Select Case mode
Case 1
Select Case re
Case Is < 2300
Fluid_Flow = "Laminar"
Case Is >= 4000
Fluid_Flow = "Transitional"
Case Else
Fluid_Flow = "Turbulent"
End Select
Case 2
Select Case re
Case Is < 2300
Fluid_Flow = "add formula"
Case Is >= 4000
Fluid_Flow = "add formula"
Case Else
Fluid_Flow = "add formula"
End Select

End Select

End Function

 

[JLGWhiz]

Have you checked this site?

http://www.cheresources.com/colebrook1.shtml

 

[Steve M.]

Does your code use the visual basic editor in excel?

How would I write a simple do loop to perform the iteration for the
colbrooke equation?

Thank,

--Steve M.

 

[Steve M.]

No, but I will. Articles appear helpful.

Have you checked this site?

http://www.cheresources.com/colebrook1.shtml

 

[JLGWhiz]

What caught my eye was the Excel spreadsheet download that they have in zip
file format. I didn't check it but it could answer all of your questions.