What do you mean by critical flow?

critical flow The flow that occurs when the flow velocity in a river channel equals the wave velocity generated by a disturbance or obstruction. In this condition the Froude number (Fr) = 1. When Fr is greater than 1 waves cannot be generated upstream and the flow is said to be supercritical, rapid, or shooting.

What is sub-critical and super critical flow?

Subcritical flow is dominated by gravitational forces and behaves in a slow or stable way. It is defined as having a Froude number less than one. Supercritical flow is dominated by inertial forces and behaves as rapid or unstable flow.

What is critical flow in a channel?

Critical flow occurs when the flow velocity in a channel equals the wave velocity generated by a disturbance or obstruction. When the wave velocity exceeds the flow velocity (Fr is less than 1) waves can flow upstream, water can pond behind an obstruction, and the flow is said to be subcritical or tranquil.

What is critical flow in civil engineering?

Critical flow is the transition or control flow that possesses the minimum possible energy for that flowrate. Critical flow has a Froude number equal to one. Critical Slope is one that sustains uniform, critical flow (yn=yc).

Is critical flow the same as choked flow?

The choked flow (often referred to as critical flow) of a flowing gas is a limiting point which occurs under specific conditions when a gas at a certain pressure and temperature flows through a restriction into a lower pressure environment.

Why is critical flow important?

Critical depth is an important value in hydraulic analysis because it is a control in reaches of non-uniform flow whenever the flow changes from subcritical to supercritical.

What is critical flow in hydraulic engineering?

Critical Flow: The variation of specific energy with depth at a constant discharge shows a minimum in the specific energy at a depth called critical depth at which the Froude number has a value of one. Critical depth is also the depth of maximum discharge, when the specific energy is held constant.

What is steady and unsteady flow?

• steady: A steady flow is one in which the conditions (velocity, pressure and cross- section) may differ from point to point but DO NOT change with time. • unsteady: If at any point in the fluid, the conditions change with time, the flow is described as unsteady.

What is super critical flow open channel?

According to the website Civil Engineering Terms, supercritical flow is defined as follows: The flow at which depth of the channel is less than critical depth, velocity of flow is greater than critical velocity and slope of the channel is also greater than the critical slope is known as supercritical flow.

What is rapid varied flow?

Rapidly Varied Flow (RVF) is a significant change in water depth or velocity of flow over a short distance. This distance can be a few times the water depth. Hydraulic jump is an example of rapidly varied flow, where the liquid level rises suddenly.

What is a shooting flow?

Torrential flow or shooting flow or super-critical flow When the depth of a flow in a channel is less than critical depth (hc), the flow is said to be a super-critical flow. Froude number is greater than 1 for super-critical flow.