Class Questions – CEEn 535 Fall 2009

11/4/09

1. Can HEC-RAS simulate flow through a horizontal or aversely sloped culvert barrel?

2. Describe the placement of cross sections for a culvert.

3. Does HEC-RAS use the 5th degree polynomial equations to calculate an inlet control rating curve?

4. The following quote is from page 6-17: "In general the higher of the two is used for the culvert portion of the solution, unless the program feels that inlet control cannot be maintained." What seems odd to you about this sentence?

5. Can HEC-RAS simulate a hydraulic jump inside of a culvert barrel?

 

11/2/09

1. What are the values of Qp, Qh, and Ql for this site?

2. I've attached the cross section for downstream calculations. What is the station and elevation of the thalweg?

3. Page H-6 lists the unit weight of sediment as 156 lb/ft^3. If the specific gravity is 2.65, is this stated unit weight correct?

4. What is the elevation of the top of the roadway?

5. What initial culvert size was tried as a replacement, and what was the embedment depth?

6. What is the D50, D84, and D95 for the proposed bed material?

7. Note that Kilgore uses DEPTH instead of hydraulic radius in the Limerinos equation.

8. How was Table H.7 obtained?

9. The last part of Step 5 evaluates the initial culvert chosen to be a replacement. Note that it says that normal depth at Qp is 2.25 ft, and that a Manning n is appropriate. How would you use HY-8 to check/verify/calculate this normal depth?

10. Same question for the first part of Step 6. Hint: Table 7.1 must be extended for shallower depths.

11. What does equation 7.6 account for?

 

10/30/09

1. Why are multiple barrel culverts on the same alignment not preferred for aquatic organism passage?

2. How would you analyze a floodplain culvert in (1) HY-8 and (2) what would you then do for this procedure?

3. What are some specific embedment guidelines?

4. Why would you want to limit interstitial flow?

5. The F* value in equation (7.3) is the ordinate on Figure 10.5 on page 418 of Sturm. On page 418, the F* reaches a constant value of about 0.03 as the particle Reynolds number increases. What does Table 7.1 in Kilgore et al. show as the Reynolds number increases?

6. For what limits of R/D84 is the Limerinos equation valid?

7. What does our author Sturm call Equation C.9 on page C-6? Hint: Chapter 4 of our text.
 

10/29/09

1. What programs did we consider?

2. Give your opinion about the merits of using a computer program that is in the (1) public and (2) commercial domain.

3. What features does HY-8 NOT have?

4. What different approaches are taken to predict HW for inlet control?

5. What were the 4 test cases designed to illustrate?

6. Which is the only program to predict brink depth?

7. Of the errors illustrated in the Figures, which error do you think is most onerous? Not specific programs or numbers, but think of the error itself.

 

9/25/09

1. For uniform flow and constant discharge, what do the terms mild, critical, and steep slopes refer to?

2. What is "limiting slope?"

3. See example 4.5. If the slope is less than 0.00409, what does that mean?

 

9/11/09

REVIEW:

1. What causes a hydraulic jump?

2. What assumptions are necessary to derive the Belanger equation?

3. What is, and what is not, conserved in the hydraulic jump governed by the Belanger equation?

PREVIEW:

1. List three or four reasons that a "hydraulic" or "drowning machine" dangerous?

2. Define u(superscript *)(subscript s), u*s

3. What's wrong with dissipating a hydraulic with a Type IX stilling basin? (Google or look it up in HEC-14).

NOTE: no questions were taken from the CE article; it's just interesting reading!

 

9/10/09

Please be prepared to answer the following for Friday about text 3.1, 3.2:

1. What are the 5 assumptions necessary in order to write the momentum equation as shown in Equation 3.1?

2. Write the momentum function. NOTE: we will NOT use the dimensionless form of the equation. Skip from page 73 equation 3.5 to last paragraph of page 80.

3. For what depth does a minimum momentum function occur?

 

9/03/09

REVIEW:

1. Describe contracted, supressed, and labrynth weirs.

2. What occurs over the sill of a broad-crested weir?

3. Why do engineers go to great mathematical lengths to see that their experimental data plot along a straight line?

PREVIEW:      (read text on Long throated flumes, including the example problem. Skim the section in WMM chapter 8 on long-throated flumes.)

1. List 5 advantages of long-throated flumes over Parshall flumes or other types of flumes

2. What are a few alternate names given to long-throated flumes?

3. How long, in the streamwise direction, should the sill be?

4. Define "modular limit"