Formulas for Drag Coefficient in a Wide Range of Re

We give two simple approximate formulas for the drag coefficient of a spherical particle [46,94] 

In a wide range of Reynolds numbers, one can use the following more complicated approximation for the drag coefficient [94]  

At Re = 1.5 x 105, one can observe the drag crisis characterized by a sharp decrease in the drag coefficient the boundary layer becomes more and more turbulent the separation point shifts abruptly to the aft area. 

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