Hydrodynamic calculation vertical lift gates
Values for calculation
Calculation
Cross-sectional area of the conduit
Area of the horizontal projection of the top seal
Minimum cross-sectional area between upstream face of the gate and upstream wall of the gate chamber
Cross-sectional area of the contracted jet issuing from the gap between the downstream face of the gate and the downstream wall of the gate chamber
Coefficient $ K_T $
Velocity before the gate
Theoretical pressure in the gate at full opening
Effective closing time factor
Under-pressure behind the gate
Pressure parameter
Gate position |
Flow coefficient |
Coefficient $ K_B $ |
Coefficient of contraction |
Gate opening |
---|---|---|---|---|
$s/s_0$ | $K_Q$ | $K_B$ | $C_c$ | $s$ |
$\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{mm}$ |
No data |
No data |
No data |
No data |
No data |
Gate position |
Loss coefficient |
Reduced free flow area in the throttle control system |
Relative flow |
Flow of water before the gate |
Water velocity before the gate |
Velocity in the contracted jet issuing from underneath the gate |
---|---|---|---|---|---|---|
$s/s_0$ | $ζ$ | $f_r$ | $Q_p$ | $Q$ | $v$ | $v_j$ |
$\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{m^3/s}$ | $\mathrm{m/s}$ | $\mathrm{m/s}$ |
No data |
No data |
$Q_p \mathrm{[-]}$
No data |
No data |
No data |
No data |
Gate position |
Loss of pressure on the gate |
Pressure on the gate |
Cavitation number |
Force on gate |
---|---|---|---|---|
$s/s_0$ | $H_L$ | $H_v$ | $σ$ | $W$ |
$\mathrm{ }$ | $\mathrm{m}$ | $\mathrm{m}$ | $\mathrm{ }$ | $\mathrm{kN}$ |
No data |
$H_v \mathrm{[m]}$
No data |
No data |
No data |
Gate position |
Downpull resulting from the difference between the pressures acting on the top and bottom surfaces of the gate |
Downpull resulting from the pressure differential acting on the horizontal protrusions of the gate |
Downpull resulting from the lip |
Downpull force |
---|---|---|---|---|
$s/s_0$ | $P_1$ | $P_2$ | $P_3$ | $P$ |
$\mathrm{ }$ | $\mathrm{kN}$ | $\mathrm{kN}$ | $\mathrm{kN}$ | $\mathrm{kN}$ |
No data |
No data |
No data |
No data |
No data |
Gate position |
Depth of water at vena contracta |
Froude number |
Aerated coefficient |
---|---|---|---|
$s/s_0$ | $h_c$ | $F_c$ | $β$ |
$\mathrm{ }$ | $\mathrm{m}$ | $\mathrm{ }$ | $\mathrm{ }$ |
No data |
No data |
No data |
No data |
Gate position |
Coefficient of under-pressure of aerated hole |
Under-pressure in the aerated pipeline |
Air flow |
Air velocity |
The flow area of the aerated hole |
The flow area of the aerated pipeline |
---|---|---|---|---|---|---|
$s/s_0$ | $f_{air}$ | $p_{air}$ | $Q_{air}$ | $v_{air}$ | $A_{air}$ | $A_{air-pipe}$ |
$\mathrm{ }$ | $\mathrm{ }$ | $\mathrm{Pa}$ | $\mathrm{m^3/s}$ | $\mathrm{m/s}$ | $\mathrm{m^2}$ | $\mathrm{m^2}$ |
No data |
No data |
No data |
No data |
No data |
No data |
No data |