;) Oh no - slagging match! Opening salvo's fired!:p
VOLUME = Unit is cubic metre (m^3).
CUMEC = CUbic MEtre per seCond (M^3.s^-1).
Defined as the VOLUME of water passing a cross-section of water (in a river), perpendicular to a bank, in one second.
If cumecs are the same for two pieces of water, then the same volume is passing the cross section BUT the cross section may not be the same.
Thus if one river is TWICE as DEEP, but the same WIDTH, it has TWICE the cross sectional area of the other and thus the VOLUME of water is passing any one spot in the DEEPER river is HALF that of the SHALLOWER river - ie the water flows past at HALF the speed (since the deeper river has TWICE as many "spots").
Yes - a lot of the bigger rivers in Europe have greater flowrates than the Vaal - either more cumecs (more water) or more flow velocity (same cumecs, but are narrower -> less cross sectional area = more flow velocity).
I have tied up some extreme flies close to 4grams myself for the Vaal - when fishing turbulent, high flow waters.
Hmm - complicated FLUID DYNAMICS & FORCE VECTORS!!
(Any other Chemical Engineers/B.Sc Physics-types out there who can help? It has been a LONG time...:p )
The shorter length of leader affected by the acting force of the water (force 90 degrees = perpendicular to leader = full force). Greater force per length, but less length.
vs
Longer length of leader affected by less than the full acting force of the water (force at say 135 to 160 degrees to leader), but with longer length.
Less force per length, but more length.
At what angle/length combination does the longer leader have less force applied than the shorter leader?
When I have the time, I will try the math...:D