D?Alembert?s Paradox states that for an incompressible and inviscid flow potential flow, drag force is equal to zero. The fluid is moving at a constant velocity with respect to its relative fluid.

For a turbulent boundary layer fluid moves in different direction producing swirls. It produces swirls due to presence of eddies. The smooth laminar boundary layer flow breaks down and transforms to a turbulent flow.

Turbulator is a device that converts a laminar flow into a turbulent flow. The turbulent flow can be desired parts of an aircraft or also in industrial applications. Turbulator is derived from word ?turbulent?.

Skin friction acts on component of profile drag. Pressure drag is also called as form drag. It mainly arises because of shape of object. Thus, correct answer is profile drag.

There will be a transition from laminar flow to turbulent flow with increase in Reynolds number. Reynolds number below 2000 is laminar flow and Reynolds number above 2000 is for turbulent flow.

A boundary layer is an important concept that refers to layer of fluid. The fluid that is in immediate vicinity of a bounding surface. The main property that affects a boundary layer is viscosity.

The relative velocity of jet is denoted as V_r1. It is relative velocity at inlet to vane. Relative velocity of inlet to vane is obtained by subtracting vectorially velocity of vane with its absolute velocity. It happens in same way for V_r2. Thus, If friction is neglected, n V_r1= V_r2.

In fluid dynamics, drag coefficient has no dimensions. It is a dimensionless quantity. Drag coefficient is used to quantify resistance of an object in a fluid environment. It is mainly used in air and water. It is denoted as C_d.

Drag coefficient is a function of Mach number. In fluid dynamics, drag coefficient has no dimensions. It is a dimensionless quantity. Drag coefficient is used to quantify resistance of an object in a fluid environment.

For a turbulent boundary layer fluid moves in different direction producing swirls. It has more skin friction drag than that of laminar boundary layer. It is more stable when compared to laminar.