So I was running through the NCEES practice problems and one of them asked to use the "critical oxygen deficit" equation for the Streeter-Phelps Dissolved oxygen sag curve. I was using Goswami's equation:
tc = (1/kr-kd) x ln[(kdLo-krDo+kdDo)/kdLo) x (kr/kd)].
I ended up getting the wrong answer, as it turns out (from the solution, google, and other sources) the equation they used was:
tc = (1/kr-kd) x ln[(1-(Do(kr-kd)/kdLo) x (kr/kd)]
This is very frustrating, there are so many little mistakes in the Goswami book that I find myself wasting my time cross checking it's validity. Which equation should I use when it comes time for the exam?
Edited by MrAnderson, 21 October 2011 - 09:33 PM.