# Homework Help: Discharge gate equation in lablace

1. Jun 4, 2010

### algibory

The discharge of irrigation gate is
q=Cd.W.L.sqrt[2g{h1-h2}] where q is the discharge of gate which is veriable value(dq/dt),Cd discharge constant,W is width of gate(constant value),L is opening gate control which is variable value(dL/dt),g is gravity constant,h1&h2 is up and downstream of water level of river ,I want to transphere in lablace equation to use it as a processor in controlling barages gate system .
Thankyou

2. Jun 12, 2010

### Axiom17

Firstly try setting out what you know more clearly.

Equation for Discharge of Irrigation Gate:

$$q=Cd\times W \times L \times \sqrt{2g(h_{1}-h_{2})}$$

Variables:

$q$ = Discharge of Gate (which is variable \frac{dq}{dt})

$Cd$ = Discharge Constant

$W$ = Width of Gate (which is constant)

$L$ = Opening Gate Control (which is variable \frac{dL}{dt})

$g$ = Gravity (which is constant)

$h_{1}$ = Upstream Water Level

$h_{2}$ = Downstream Water Level

Just makes it easier to see what's what when attempting to solve the problem.

Secondly, "transphere in lablace equation" .. I presume you mean that you want to use the Laplace Equation

http://en.wikipedia.org/wiki/Laplace's_equation

Thirdly/Finally, it's a bit unclear exactly what you want to do, and also could you detail what work you have done so far on this problem.