## Tuesday, November 15, 2011

### Qfull in SWMM 5 for various levels of y/yFull in a Circular Pipe

Subject:  Qfull in SWMM 5 for various levels of y/yFull in a Circular Pipe

Here is a table that shows the value of Q/Qfull for various levels of y/yFull or d/D in SWMM5.  The full flow if you loop off the top of a circular pipe at the 0.83 level would be about 1.01 times Qfull for the whole pipe.  Figure 1 shows how the flows are calculated at various values, Table 1 and Figure 2 show the values of a/aFull, r/rFull and q/qFull for various values of y/yFull.

 Figure 1.   How Qfull and Qmax are calculated in  SWMM 5 based on the roughness, slope and a lookup table for area and hydraulic radius for a circular pipe.

 y/yFull a/aFull r/rFull Q/qFull 0.00000 0.00000 0.01000 0.00000 0.02000 0.00471 0.05280 0.00066 0.04000 0.01340 0.10480 0.00298 0.06000 0.02445 0.15560 0.00707 0.08000 0.03740 0.20520 0.01301 0.10000 0.05208 0.25400 0.02089 0.12000 0.06800 0.30160 0.03058 0.14000 0.08505 0.34840 0.04211 0.16000 0.10330 0.39440 0.05556 0.18000 0.12236 0.43880 0.07066 0.20000 0.14230 0.48240 0.08753 0.22000 0.16310 0.52480 0.10612 0.24000 0.18450 0.56640 0.12630 0.26000 0.20665 0.60640 0.14805 0.28000 0.22920 0.64560 0.17121 0.30000 0.25236 0.68360 0.19583 0.32000 0.27590 0.72040 0.22172 0.34000 0.29985 0.75640 0.24893 0.36000 0.32420 0.79120 0.27733 0.38000 0.34874 0.82440 0.30662 0.40000 0.37360 0.85680 0.33702 0.42000 0.39878 0.88800 0.36842 0.44000 0.42370 0.91760 0.40009
Table 1.   Table  of y/yFull and Q/Qfull based on a/aFull and r/rFull

 Figure 2.   Graph of values in Table 1