MANPIP

[Thomas Klemm]

(04-08-2014 09:29 PM)Jerussi Wrote:  I left the Q= out of "The program would prompt you for "n=", "D=", "S=", "y=" and you would enter the knowns and R/S through the unknowns." it should have read: The program would prompt you for "n=", "Q=", "D=", "S=", "y=" and you would enter the knowns and R/S through the unknowns.

That makes more sense. Was it possible to solve for D or y? Because that appears to be a little more difficult.

Quote:Qp and Qf are both Q (flow in cubic feet/sec)
Qp is partial flow and is derived from the Manning's equation.

Would you enter Qp in the program when prompted for "Q="?

Quote:Qf is full flow where the equation changes to Q=VA, where V is velocity in Ft/sec and A is the cross sectional Area of the inside of the pipe in Feet.

Does that mean: \(Qf=V\cdot\frac{\pi D^2}{4}\)?

Could you provide some examples for the calculations?

Though I'm sure this isn't yet what you had here's a first approach:

Code:

LBL "MANNING"
"N = ?"
PROMPT
FS?C 22
STO 00
"D = ?"
PROMPT
FS?C 22
STO 01
"S = ?"
PROMPT
FS?C 22
STO 02
"Y = ?"
PROMPT
FS?C 22
STO 03
1
RCL 03      ; y
2
*
RCL 01      ; d
/
-
ACOS
2
*
STO 04      ; theta = 2 arccos(1 - 2 y / d)
ENTER
SIN
-
RCL 01      ; d
X^2
*
8
/
STO 05      ; A = (theta - sin(theta)) d^2 / 8
RCL 04      ; theta
/
RCL 01      ; d
/
2
*           ; R = A / P
LASTX       ; 2
3
/
Y^X         ; R^(2/3)
RCL 02      ; S
SQRT
*
RCL 00      ; n
/
1.49        ; k
*
STO 06      ; V = k R^(2/3) S^(1/2) / n
RCL 05      ; A
*
STO 07      ; Q = V A
"N = "
ARCL 00
PROMPT
"D = "
ARCL 01
PROMPT
"S = "
ARCL 02
PROMPT
"Y = "
ARCL 03
PROMPT
"A = "
ARCL 05
PROMPT
"V = "
ARCL 06
PROMPT
"Q = "
ARCL 07
PROMPT
END

You are only asked for n, D, S and y. But you don't have to re-enter them when they aren't different from the last calculation. Only A, V and Q are calculated.

Cheers
Thomas