A pressure gradient is a change in pressure over a specific distance or area. It can be described as the force per unit area that drives a fluid flow.
The pressure gradient across a flat plate with flow is zero because there is no change in pressure in the direction of flow. This is due to the boundary layer that forms on the surface of the plate, which reduces the velocity and therefore the pressure difference across the plate.
The pressure gradient across a flat plate with flow is important because it affects the velocity and flow characteristics of the fluid. It also plays a role in determining the lift and drag forces on the plate, which are important in aerodynamics and fluid dynamics.
The pressure gradient across a flat plate with flow can be affected by the viscosity of the fluid, the velocity of the flow, the shape and size of the plate, and the angle of attack. Surface roughness and other external factors can also have an impact.
The pressure gradient across a flat plate with flow can be calculated using the Bernoulli's equation, which takes into account the velocity, density, and pressure at different points along the plate. Alternatively, it can be measured experimentally using pressure sensors placed at various points on the plate.