# I'm trying to find out the drag coefficient of a simple cylinder, the results are showing wrong, can you please look into the give data and let me know how to find the Drag coeff of the cylinder ?with accurate results!

Question asked by Naga Gopal on Jun 19, 2019

Model: 1

Size: Dia 127x650 mm.

Wind Velocity in X Direction = 47M/S

Input data given : General Settings

Analysis type – External

Fluids: AIR (Gases)

Flow type: Turbulent

Thermodynamic Parameters:

Parameters - Pressure, Density

Pressure- 1325 Pa

Density 1.2kg/m^3

Velocity Parameters:

Velocity in X Direction: 47 m/s

Velocity in Y Direction: 0 m/s

Velocity in Z Direction: 0 m/s

Computational Domain Size:

 X, -X Y, -Y Z, -Z Study A.     1.58, -1.58 0.65, -0.65m 1.58, -1.58 m Study B.     2.22, -2.22m 0.25, -0.25m 2.22, -2.22m

Goals: Global Goal

surface Goal

Applied Equation:

({GG Force (X) 1} *2)/ (1.2*47^2*3.14*0.5*0.127*0.65) (Based on drag coefficient formula)

({SG Force (X) 1} *2)/ (1.2*47^2*3.14*0.5*0.127*0.65)

Standard Values:  Cd – 0.5     (Dvd >6) (Standard Values Reference from IS 875 Part 3)

Standard code IS 875 Link ( https://archive.org/details/gov.law.is.875.3.1987 ) Page no: 40   Table no:23

Achieved Values:

 Global Goal Surface goal Cd Value Average Cf Value Average Study A.   0.81 0.81 0.81 0.81 Study B.   0.81 0.81 0.81 0.81

EDITED BY MODERATOR: Moved to the Flow Simulation sub-space. Please post to the appropriate sub-space when one exists.