# I Stokes Law/Drag Force corrections?

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1. Mar 6, 2016

### tomdodd4598

Hi there,

I have recently been experimenting with solid metal spheres being let to fall through fluids of different viscosities and have recently been introduced to the 'Ladenburg correction'. This correction multiplies the measured velocity of the sphere to obtain the 'correct' velocity used in the Stokes Law. However, this correction is only accurate when the ratio of the radius of the sphere to the radius of the tube the fluid is in is about 0.1 or lower. Instead, Francis and Little's general correction can be used, and is valid for ratios up to around 0.83.

The problem I have is the following: Sometimes, I am using fluids, such as water, which are not viscous enough for laminar flow, hence not viscous enough for Stokes' Law to be valid (the drag force formula is used instead). Is there a known wall correction factor for fluids such as this, or is the correction very small?