How can you determine that the flow in a river is subcritical critical or supercritical without taking any measurment?

One way to determine if the flow is subcritical or supercritical is to look at the water surface around obstructions to the flow. If the flow is fairly flat, then it’s subcritical. If there are large local changes in the surface height, then it’s supercritical.

How do you know if a flow is supercritical or subcritical?

If Fr is greater than 1.0, flow is supercritical; if it is under 1.0, flow is subcritical. Fr is 1.0 for critical flow conditions.

Why is the state of flow and critical depth of river or canal determined?

Answer: The flow of water will determine the extent of displacement of these particles. So, depending upon both these physical parameters, it can be ascertained how much will be the displacement & settlement of these various items. For settlements, depth of the river will say how much of these items have settled.

What is critical depth in open channel flow for a given average flow velocity how is it determined?

The critical depth for a rectangular channel can be calculated from the fact that the Froude number is equal to one at critical flow conditions. For a rectangular channel , this fact leads to the equation: Vc/(gyc)1/2 = 1, where the subscript c is used to indicate critical flow conditions for the velocity and depth.

What is subcritical flow in fluid mechanics?

Subcritical occurs when the actual water depth is greater than critical depth. 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 has a Froude number greater than one.

How do you determine if a hydraulic jump will occur?

A hydraulic jump occurs when the upstream flow is supercritical (F>1). To have a jump, there must be a flow impediment downstream. The downstream impediment could be a weir, a bridge abutment, a dam, or simply channel friction. Water depth increases during a hydraulic jump and energy is dissipated as turbulence.

What is meant by subcritical flow?

Subcritical occurs when the actual water depth is greater than critical depth. 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 subcritical turbulent flow?

Subcritical flow occurs when the combined Froude number is less than unity such that waves can travel in both directions.

How does critical flow occur?

critical flow Critical flow occurs when the flow velocity in a 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.

How do you calculate critical flow?

1. The critical flow velocity equals V c = g d c in a rectangular channel. 2. For a constant specific energy E, equation (2.11) is a cubic equation in terms of the water depth d.

What is critical and subcritical flow?

Subcritical flow is dominated by gravitational forces and behaves in a slow or stable way. Supercritical flow has a Froude number greater than one. 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.

One way to determine if the flow is subcritical or supercritical is to look at the water surface around obstructions to the flow. If the flow is fairly flat, then it’s subcritical. If there are large local changes in the surface height, then it’s supercritical.

What is critical flow?

Critical flow is the dividing condition between supercritical flow and subcritical flow. Let’s take a look at the conditions for critical flow first. It’s the dividing line between subcritical and supercritical flow.

What is the difference between subcritical and supercritical boilers?

The fundamental difference between subcritical and supercritical flow lies in the density of the flow. In a supericritical boiler the density difference is very low between steam and water and no latent heat of vaporization. Efficiency depends on the temperature and not on heat quantity.

What is the Froude number in critical flow?

The Froude Number as Related to Critical Flow The Froude Number is a dimensionless parameter used in connection with open channel flow. For flow in a rectangular channel, the Froude Number is defined as: Fr = V **/ (gy)1/2**, where the variables in the definition are as defined in the previous section.