What is the energy loss in the basin with and without blocks

Assignment Help Civil Engineering
Reference no: EM13322528

Background: At dams, a usually rectangular channel is used as an overflow channel to drain the reservoir formed behind the dam when the water level in the reservoirs gets too high. Since dams are usually quite large structures, this means that the water moving through the spillway has a lot of energy and the velocity will be very high at the bottom of the spillway. Therefore, a stilling basin is used at the base of the spillway to dissipate some of this energy before the high velocity fluid moves in into the downstream river channel. Since hydraulic jumps are very good energy dissipators, the basins are often designed so that a jump forms within the basin. A jump will form if the river water depth is equal to the subcritical sequent depth of the flow into the stilling basin. If the river depth is larger than the subcritical sequent depth, a submerged hydraulic jump forms. Sometimes, concrete blocks called "baffle blocks" are placed on the stilling basin floor to help the hydraulic jump form within the basin. The baffle blocks decrease the momentum of the flow (by an amount equal to the drag on the blocks) and allow a jump to form under a larger range of tailwater (water depths in the downstream river channel) than would normally occur. Consider a spillway and stilling that are rectangular in shape with a width of 22.5 m.

The floor of the stilling basing is at an elevation 240.0 m above a datum. The incoming flow has a flow depth of 1.0 m at the design discharge of 275 m3/s. Within the basin are 17 baffle blocks placed on the bed of the channel, each 0.5 m high and 0.85 m wide.

a. Assuming a drag coefficient Cd of 0.6 for the baffle blocks based on the upstream velocity and combined frontal area of the blocks, calculate the sequent depth required to form a jump with the blocks and compare this value to the sequent depth required to form a jump without baffle blocks.

b. What is the energy loss in the basin with and without the blocks?

c. If the tailwater elevation for Q=275 m3/s is 246.5 m, will the stilling basin performed as designed? (i.e. Do you have enough tailwater for the jump to form and, if it does, it is submerged?)

Reference no: EM13322528

Questions Cloud

What is the cross sectional area of this solenoid : A solenoid is 1.6 m long and has 530 turns per meter. what is the cross sectional area of this solenoid if it stores .31 J of energy when it carries I=14A
What characteristics must the convertible bonds display : What characteristics must the convertible bonds display in order to justify the accounting treatment followed on initial recognition and how was the portion of the bonds assigned to debt on initial recognition valued?
State the electron configurations for the ions : Write the electron configurations for the following ions. You should use the noble gas abbreviations: Te2-, Mg+, As+, I-, Fe3+, N3-, Sn4+, Tl4+
State electron configuarations : Iron exhibits three common oxidation states, as seen in Fe, Fe2+, and Fe3+. Write electron configuarations for each of these species using the noble gas abbreviations and determine the n and l quantum numbers of the electron that is removed in goi..
What is the energy loss in the basin with and without blocks : If the river depth is larger than the subcritical sequent depth, a submerged hydraulic jump forms. Sometimes, concrete blocks called "baffle blocks" are placed on the stilling basin floor to help the hydraulic jump form within the basin.
What project management tools : What project management tools do you feel are most useful and why?
Determine the intervals of increase or decrease : (a) Find the intervals of increase or decrease. (b) Find the local maximum and minimum values. (c) Find the intervals of concavity and the in?ection points. (d) Use the information from parts (a)-(c) to sketch the graph. G(x)= 5x^(2/3)-2x^(5/3)
Determine what will be the height above datum of a point b : If the free surface at a distance from the axis of the vortex, which is sufficient for its effect to be negligible, is 180 mm above datum, what will be the height above datum of a point B on the free surface at a radius of 100 mm
A professional journal on a current hr-related topic : Choose a research article from a professional journal on a current HR-related topic. The article should contain information on an actual study of a hypothesis with corresponding results.

Reviews

Write a Review

Civil Engineering Questions & Answers

  Depth of aggregate of wheel load over soil

A 2000-lb wheel load is to be supported by aggregate over soil with a maximum bearing pressure of 1000 lb/sqft. What depth of aggregate is needed if the angle theta is 40 degrees?

  Calculate how high will the liquid rise in the small tube

A weightless piston is placed on the liquid surface and the water level stabilizes (also in the small tube) to a level of h. Next, a weight of 10 kg is placed on the piston causing the liquid in the small tube to rise.

  Determine the elastic modulus of the composite material

An SAE steel wire (1mm diameter) is coated with another cover to form a composite material with diameter of 2 mm. a) determine the elastic modulus of the composite material;

  What is the total volume of the vocs emitted each day

Assume that there were 1,100,000 vehicles making a 28.5-mi round trip per day, the average vehicle emission rate for VOCs is 1.3 g/VM , and the molecular weight of the VOC emissions from the mobile sources can still be represented by that of metha..

  Determine the acre-feet of water that can be impounded

An earth fill is constructed across a drainage. Closed contours at the 1000, 1040 and 1080 foot levels define areas of 680,000; 1,200,000; and 1,325,000 square feet respectively.

  Explain how to describe the operation of series rl circuit

The discussion must address phase angle relationships of current and voltage. The answer must include the effect of source frequency on the voltage drops across the resistor and the inductor at very low and very high frequency values.

  How does the result differ from the case of oblique impact

In the Civil War there were numerous incidents in which the bullet fired from a Union soldier's rifle struck and fused with the bullet from a Confederate's rifle. Assume the impact scenario.

  Determine acceleration of rod and reaction at a and b

The motion of the 2.5-kg rod AB is guided by two small wheels which roll freely in horizontal slots. If a force P of magnitude 8 N is applied at B, determine (a) the acceleration of the rod, (b) the reaction at A and B.

  Calculate how many lbs of co2 are produced per gallon

Diesel fuel has an average chemical formula of C12H23 and a density of 6.45 lb/gal. Calculate how many lbs of CO2 are produced per gallon of diesel burned (assume complete combustion).

  How much money will be saved in energy each year

An electric water heater held at 140 °F is kept in a 70 °F room. When purchased, its insulation is equivalent to R-5. An owner puts a 25-ft2 blanket on the water heater, raising its total R value to 15

  Radius of the steel wire ehen stretching with other wire

The aluminium wire has a radius of 1.1mm. What must be the radius of the steel wire if it is to stretch the same distance as the aluminium wire, so that the two wires maintain equal lengths after the masses are attached?

  Explain how to present the geological profile of the terrain

Based on information provided in the survey bulletins and knowing that the landfill is located in the municipality of Duque de Caxias, on the shore of Guanabara Bay opposite Governor's Island (Galeao Airport)

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd