What is the conjugate depth?
In fluid dynamics, the conjugate depths refer to the depth (y1) upstream and the depth (y2) downstream of the hydraulic jump whose momentum fluxes are equal for a given discharge (volume flux) q. The depth upstream of a hydraulic jump is always supercritical.
Conjugate, or sequent, depths are the paired depths that result upstream and downstream of a hydraulic jump, with the upstream flow being supercritical and downstream flow being subcritical.
- Although momentum is conserved throughout the hydraulic jump, the energy is not. There is an initial loss of energy when the flow jumps from supercritical to subcritical depths. The resulting loss of energy is equal to the change in specific energy across the jump and is given by the equation for ΔE below.
- Fr = 1, critical flow, Fr > 1, supercritical flow (fast rapid flow), Fr < 1, subcritical flow (slow / tranquil flow) The Froude number is a measurement of bulk flow characteristics such as waves, sand bedforms, flow/depth interactions at a cross section or between boulders.
- The Cavitation number (Ca) is a dimensionless number used in flow calculations. It expresses the relationship between the difference of a local absolute pressure from the vapor pressure and the kinetic energy per volume, and is used to characterize the potential of the flow to cavitate.
Theory and derivation of alternate depth relationship. In the open-channel flow of rectangular channels, the alternate depth equation relates the upstream( y1 ) and downstream( y2 ) steady-state flow depths of a flow that encounters a control device, such as a sluice gate, which conserves energy for a given discharge.
- Viscosity is the measure of a substance's resistance to motion under an applied force. The result is typically expressed in centipoise (cP), which is the equivalent of 1 mPa s (millipascal second). Shear stress is the force per unit area required to move one layer of fluid in relation to another.
- Adding soap lowers the water's surface tension so the drop becomes weaker and breaks apart sooner. Making water molecules stick together less is what helps soaps clean dishes and clothes more easily.
- Spreading coefficient is a measurement of the ability of one liquid to spontaneously spread across another.
Updated: 9th September 2018