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 Momentum thickness?
Momentum thickness calculator uses Momentum Thickness = Hydrodynamic Boundary Layer Thickness/7 to calculate the Momentum Thickness, The Momentum thickness formula is defined in relation to the momentum flow rate within the boundary layer. Momentum Thickness is denoted by θ symbol.
How to calculate Momentum thickness using this online calculator? To use this online calculator for Momentum thickness, enter Hydrodynamic Boundary Layer Thickness (𝛿hx) and hit the calculate button. Here is how the Momentum thickness calculation can be explained with given input values -> 0.285714 = 2/7.