Head Loss in Pipe Network
Consider an overhead tank with a constant head (some mechanism maintains the constant head) kept at a height H from a reference line. Through a vertical pipe the fluid is brought down to the reference line and ejected into a glass tank as a horizontal jet.
I need to find the Height H required to obtain a very low Reynold's Number (=100) jet.
I am using the bernoulli's equation with head loss:
p1/rho*g + v1^2/2g + H = p2/rho*g + v2^2/2g + 0 + Head_loss
1 is the free surface of overhead tank and 2 is pipe exit in a glass tank. Now, I am writing Head loss as Head_Loss = (64/Re)*(H/D)*(Vavg^2/2g)
All the other terms are fine. But the issue is that the Head Loss depends on the unknown height H, which on simplifying the equation gives me a term:
(1  (64*Vavg^2/2g*D)/Re)*H = (1  k/Re)*H = Other P and V terms
for changes in Reynolds Number sometimes I am seeing that this coefficient is becoming zero or negative giving me a singularity or a negative height for the tank placement.
How is this physically possible, what am I doing wrong?
