what is unit discharge in case of trapezoidal channel, as q=Q/B in case of rectangular channels
Taher:
As a Mechanical Engineer it has been a very long time since I did any calculations with regard to open channel flow. I am assuming based on my review of the subject that
q = Flow per unit with of the channel
Q = Total flow within in the channel
B = The width of the channel.
The link below appears to have a lot of calculators for evaluating the flow though channels including trapezoidal ones. I hope it can guide you in your understanding.
Because of the different flow conditions along the sloped sides I do not think that it is really possible to get a realistic unit discharge rate as with the rectangular channel.
Niel