CIV E 530 - OPEN-CHANNEL HYDRAULICS
SPRING 2014
LAB No. 9 (PHYSICAL):  HYDRAULIC JUMP

Objectives:

1. To demonstrate the principles of the hydraulic jump.

2. To calculate the energy loss through the jump.

Formulas:

Theoretical formulas for the hydraulic jump:

Sequent depth:  y2 = (y1 / 2) [ (1 + 8F12)1/2 - 1 ]         [1]

Discharge:  Q = F1 B (g y13)1/2         [2]

Upstream velocity:  v1 = Q / (B y1)         [3]

Upstream head:  H1 = y1 + v12/(2g)         [4]

Downstream velocity:  v2 = Q / (B y2)         [5]

Downstream head:  H2 = y2 + v22/(2g)         [6]

Energy loss:  ΔE = (y2 - y1)3 / (4y1y2)         [7]

Procedure:

  1. With the flume setup running at a given discharge, with a steady hydraulic jump developed (F1 around 4.5), measure:

    1. Initial depth y1

    2. Sequent depth y2

    3. Channel width B

  2. Calculate the Froude number solving for F1 with Eq. 1.

  3. Calculate the discharge Q with Eq. 2.

  4. Using Equations 4 and 6, calculate energy loss based on hydraulic heads:  ΔEm = H1 - H2

  5. Using Equation 7, calculate energy loss ΔEc based on depths y1 and y2.

  6. Compare ΔEc with ΔEm.

  7. Write a short report summarizing and commenting on the findings.