Rapidly varied flow pdf

Supercritical velocity is greater than critical velocity and subcritical velocity is less than the critical velocity. In hydraulic jump the flow is from supercritical flow unstable to a sub-critical flow. For supercritical flow depth is less, so area of flow will be less and velocity will be more. Similarly for subcritical flow depth is more so area of flow will be more so velocity will be less to maintain a constant discharge. A hydraulic jump occurs when flow changes from a supercritical flow unstable to a sub-critical flow stable.

Conjugate depth: The conjugate depths refer to the depth upstream and the depth downstream of the hydraulic jump whose momentum fluxes are equal for a given discharge. In a hydraulic jump, the depths on the two sides are 0. The head loss in the jump is nearly. Consider the occurrence of a surge at the water surface of a wide rectangular channel flow, as in the figure.

Joint application of continuity and momentum principles will indicate the surge front speed V W , to be. Celerity or Surge Front Speed : It is the speed at which the surge or wave is moving with respect to fluid medium. It means if there is a surge in fluid medium, then the surge will move at a different speed compared to fluid medium and that relative speed is known as surge front speed or celerity.

If surge front speed is denoted by V w and y 1 and y 2 are the depth of water before and after surge respectively, then. Start Learning. Sub-critical Super-critical Critical Not possible. Weak jump Oscillating jump Steady jump Strong jump. Get Started for Free Download App. Hence flow is supercritical in case of S 2 , S 3 and M 3 profiles. Gradually varied flow rapidly varied flow steady flow normal flow. Answer Detailed Solution Below Option 2 : rapidly varied flow.

Steady and Unsteady flow: If the flow parameters such as velocity, acceleration, discharge do not change with time then flow is called steady flow, otherwise, flow is un-steady.

Gradually varied and Rapidly varied flow: If flow parameters such as velocity, acceleration, discharge changes with space, then flow is called non-uniform flow or varied flow. The examples for above kind of flows are given below: Type of flow Example Steady and uniform flow Flow in prismatic channel Steady but gradually varied flow Back water curve due to obstruction Steady but rapidly varied flow Hydraulic jump Unsteady and Gradually varied flow Flood flow in river Unsteady and rapidly varied flow Surge The surge means a sudden powerful forward or upward movement of water or powerful disturbance in water which could not be possible in gradually varied flow and steady flow.

Answer Detailed Solution Below Option 3 : 0. Concept : Hydraulic jump: Whenever supercritical flow merges into a subcritical flow, a sudden jump is formed to reduce the energy of the water depth, is known as a hydraulic jump. Answer Detailed Solution Below Option 4 : steady jump. Explanation: The hydraulic jumps in horizontal rectangular channels are classified into five categories based on Froude number F1 of the supercritical flow as: Range Type 1.

Answer Detailed Solution Below Option 2 : 0. Answer Detailed Solution Below Option 2 : 8. Answer Detailed Solution Below Option 1 : Concept: A hydraulic jump is formed when the supercritical flow conditions change to subcritical flow. The above formula is applicable only in a horizontal, frictionless rectangular channel. For any other cross-section, momentum equation and continuity equation is used to derive the formula. Rapidly varied flow: When the flow properties such as velocity, density, etc.

Depending upon the changes it can be either gradually or rapidly varied flow. Discharge is maximum for a given specific energy.

Specific force is minimum for a given discharge. Answer Detailed Solution Below Option 2 : hydraulic jump. Concept- A hydraulic jump occurs when the flow changes from a supercritical flow unstable to a sub-critical flow stable. Important Points Supercritical velocity is greater than critical velocity and subcritical velocity is less than the critical velocity. Answer Detailed Solution Below Option 4 : critical flow. The characteristics of critical flow are: i The specific energy and specific force are minimum for the given discharge.

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