What causes flow separation?

Separation occurs due to an adverse pressure gradient encountered as the flow expands, causing an extended region of separated flow. The part of the flow that separates the recirculating flow and the flow through the central region of the duct is called the dividing streamline.

When a fluid flows over a stationary solid surface the fluid velocity at the fluid solid interface is?

At the fluid-solid interface, the force of attraction between the fluid particles and solid particles (Adhesive forces) is greater than that between the fluid particles (Cohesive forces). This force imbalance brings down the fluid velocity to zero.

When the velocity of particle of liquid flowing through pipe line at any given point is constant the flow is?

The flow of fluid is said to be steady if at any given point, the velocity of each passing fluid particle remains constant.

What is attached flow?

Attached flow is the flow which has not separated from the body. For example in an airfoil, at low angles of attack the flow is attached ie the streamlines are such that they “stick” to the body.

Why does flow reattach?

The flow usually wants to maintain its normal condition based on related parameters, if this is not interrupted by any external disturbances. So, after the separation, it gets its normal state at the downstream region overcoming the disturbed environment. Therefore, the reattaching of flow occurs.

When a fluid flows over a solid surface the *?

When liquids flow over solid surfaces, their flow velocity in the immediate vicinity of the surface is zero. ‘By specially coating the surface, the boundary layer velocity can be increased. This also has the effect of reducing the shear forces within the liquid and of increasing its mean flow velocity.

What causes velocity gradient?

The difference in velocity between adjacent layers of the fluid is known as a velocity gradient and is given by v/x, where v is the velocity difference and x is the distance between the layers. …

When can you use Bernoulli’s equation?

You should only use Bernoulli’s equation when ALL of the following are true: Along a Streamline – Bernoulli’s equation can only be used along a streamline, meaning only between points on the SAME streamline. mixed jets, pumps, motors, and other areas where the fluid is turbulent or mixing.