Breadth - Water Resources Flashcards
(38 cards)
if pressure is measured from a vaccuum then what type of pressure is it?
absolute pressure
if pressure is measured from a gage then what type of pressure is it?
gage
how do you convert ftsq per sec to gpm?
multiple fps by 449
what is the equation for pressure head?
pressure / gamma
if you have a pump in a bernoulli’s equation problem what side of the equation should it go on?
the left side
if you have a turbine, valve loss, or friction losses, where should it go in the bernoulli’s equation?
it should be added to the right side of the equation
what is another name for the bernoulli’s equation?
energy grade line
what is the HGL?
it is the hydraUlic grade line and it depicts potential energy plus pressure head
how do you convert MGD to cfs?
you must multiply MGD by 1.55
how can you calculate friction losses?
you can use the darcy weishback or hazen williams equation
what does it mean to have turbulent flow?
it means that the velocity are so great that it cannot dampen out disturbances caused by surface roughness
what is laminar flow?
its a smooth flow in water with a relatively low velocity. surface area ofd the pipe is probably smooth as well
what are the steps to solving a darcy-weisbach problem?
first calculate velocity, then determine the reynold’s number and the flow type, then plug into equation and solve
can you convert head loss to pressure drop? if so what is the conversion?
yes you can. divide your head by 2.31 to get psi
1 psi = 2.31 ft
when calculating head loss in pipes what is important to remember?
always include the exit and entrance values when finding the minor head losses
when froude’s number is 1, what does that mean?
it means that the flow is critical and unstable
what is a hyteograph?
a hyteograph measures the rainfall intensity during a period of time
when using the average method in hydrology what is important to remember about the 1/n value?
n is equal to number of gauges minus the number of missing readings
what is IDF?
it is a curve that gives the duration and the intensity of a storm
what is a storm frequency?
it determines the probability of a certain storm occuring or not occuring
what is the reliability formula for rain storms?
reliability is the event of recurrence of it NOT occurring in N years
P(f) = (1/1/F)^n
what is effective rainfall?
effective rainfall is total rainfall - losses. aka the portion of rainfall that is available as overland supply
what is a hydrograph?
it is a graph showing runoff with respect to time for a given rainfall event
how do you find the direct runoff using the graph?
you need to find the area of the triangle so bh(1/2)
