What is external flow?
In fluid mechanics, external flow is such a flow that boundary layers develop freely, without constraints imposed by adjacent surfaces. Accordingly, there will always exist a region of the flow outside the boundary layer in which velocity, temperature, and/or concentration gradients are negligible. It can be defined as the flow of a fluid around a body that is completely submerged in it.
An example includes fluid motion over a flat plate (inclined or parallel to the free stream velocity) and flow over curved surfaces such as a sphere, cylinder, airfoil, or turbine blade, air flowing around an airplane and water flowing around the submarines.
How to Calculate Local friction coefficient for external flow?
Local friction coefficient for external flow calculator uses Local Friction Coefficient = 2*Wall Shear Stress/(Density*Free Stream Velocity^2) to calculate the Local Friction Coefficient, Local friction coefficient for external flow formula is defined as a dimensionless measure of the shear stress at the surface of a flat plate, characterizing the resistance to fluid flow over the plate's surface, and is used to predict the frictional forces acting on the plate. Local Friction Coefficient is denoted by Cfx symbol.
How to calculate Local friction coefficient for external flow using this online calculator? To use this online calculator for Local friction coefficient for external flow, enter Wall Shear Stress (τw), Density (ρ) & Free Stream Velocity (u∞) and hit the calculate button. Here is how the Local friction coefficient for external flow calculation can be explained with given input values -> 1.4E-6 = 2*801189.2/(997*70^2).