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 Wall shear stress?
Wall shear stress calculator uses Wall Shear Stress = (Local Friction Coefficient*Density*(Free Stream Velocity^2))/2 to calculate the Wall Shear Stress, Wall shear stress formula is defined as a measure of the frictional force per unit area exerted by a fluid flowing along a solid surface, typically used to analyze the flow behavior over a flat plate, and is an important parameter in understanding the flow dynamics and its effects on the surface. Wall Shear Stress is denoted by τw symbol.
How to calculate Wall shear stress using this online calculator? To use this online calculator for Wall shear stress, enter Local Friction Coefficient (Cfx), Density (ρ) & Free Stream Velocity (u∞) and hit the calculate button. Here is how the Wall shear stress calculation can be explained with given input values -> 801189.2 = (0.328*997*(70^2))/2.