Flow over sphere low reynolds number
 

Inlet velocity is 200e-6 m/s and diameter of sphere is 5e-6 m . I want to calculate the drag force acting on the sphere but when i compare it with the analythical solution which is 6*pi*eta*U*R the results are completely different . Please help???

Hy Kadir,

Do you use the definition of the drag forces as the drag coefficient multiplied by 0.5*inlet_density*inlet_velocity^2*Impact_Surface?
If you have a Sphere you must define the Impact_Surface as the area of the cercle: (Pi*Diameter^2 )/ 4 .

Best regards,
Anca

Yes i know that formulation for sure however this flow is a micro flow which has a reynolds number of 0.001 in such reynolds number drag coefficient is not constant as a result in this case i cant use that formulation