day 1-2 from the class

[Road Guy]

Well we worked about 25 different versions of manning equation

(I guess thats a hint?)

this seems like a really good prep class, but the instructors are a little too overconfident, they basically said that 90% of the CERM is crap and all you really need (other than their book) is the appendixes and a few of the charts / formulas... (found that a little funny)

This is where we spent the most of our time when we were not doing the mannings marathon:

the energy equation about 10 times

darcy & hazen williams (about 10 each)

Froude #

Reynolds #

critical depth

hydraulic jump

1 pump question (really a hazen williams / losses question)

******************************************************

I will try and scan the cheat sheet list of formulas if I can get time, most likely it probably wont be until next week though.

Here are 2 problems to chew on:

1. CERM Porblem 20A-B(Page 19.5) they said this was a "good" problem...

2. A 42" concrete culvert pipe is 250' long, and has a slope = .006. The culvert entrance is flush & square edged. Tailwater level is just above the crown of the barrell, headwater= 5' above the crown of the culverts inlet. What is the capacity in cfs?

A. 60

B. 80

C. 100

D. 120

 

[Road Guy]

also convication (sp?) is most likely to happen just before the pump on the suction side of the pump

dude said that about 10 times also :dunno:

I dont recall hearing that in my college days, so just passing along...

 

[DVINNY]

CAVITATION

You should really be aware of the various reasons that cause cavitation to a pump

 

[Blu1913]

Thanks TONS Roadguy for the info...

For that problem you mentioned...what version of the CERM are you using? ON page 19-5 of my CERM (10th edition) the problem is #19.2. Can you clarify?

 

[GTScott]

Good info. For your money, be sure to soak up all you can.

As for cavitation, I see that as a good qualitative AM question. Realize that cavitation can be affected by pump elevation, losses in the suction piping, fluid temperature, and a few other things.

As for mannings, if you happen to get a few different versions of mannings (solved for Q, S, D, full pipe, etc.) I would love to see all of the variations that they come up with.

A friend of mine in your class spoke of someone who knew how to program the 33S to do all sorts of wonderous things...somehow I was thinking that might have been you.

 

[Timber]

From Mannings equation, full flow 42" pipe will convey 77.92 cfs, under gravity flow. Since there is a noticble diffence in head pressure, what impact will the differnce in the Hydraulic Grade Lines have on the overall conveyance capacity in the problem above?

Would the Submerged Orifice Equation be utilized to examine this?

Any thoughts?

 

[DVINNY]

A friend of mine in your class spoke of someone who knew how to program the 33S to do all sorts of wonderous things...somehow I was thinking that might have been you.

Definately not our RoadGuy, LOL!!!!!!

:ass:

 

[Road Guy]

no that wasnt me, I tried checking the "list" to find another guy who matched the name you gave me to introduce myself. the hotel threw away my "engineerboards.com" propaganda I printed out in the break room <_<