Forced hydraulic jump on artificially roughened beds

Download

index.pdf

Date

2006

Author

Şimşek, Çağdaş

Metadata

Show full item record

Item Usage Stats

583
views

136
downloads

In the scope of the study, prismatic roughness elements with different longitudinal spacing and arrangements have been tested in a rectangular flume in order to reveal their effects on fundamental characteristics of a hydraulic jump. Two basic roughness types with altering arrangements have been tested. Roughness elements of the first type extends through the channel width against the flow with varying length and pitch ratios for different arrangements. The second type is of staggered essence and produced by piecing the roughness elements defined in the initial type into three parts which are equal in length. The doublet formed from the pieces on the sides is shifted to the consequent row to make two successive roughness rows encapsulate the channel span completely. Staggered roughness type is formed with the repetition of this arrangement along the flume. Independent of their type and arrangement, the entirety of roughness elements are embedded in the channel bed in order to avoid their protuberance into the flow, based on the presumption that the crests of the roughness elements levelled with the channel inlet would be less exposed to caving effects of flow than the protruding elements. In the study, influence of the proposed roughness elements on the fundamental engineering concerns as the length, height (tail water depth) and energy dissipation capacity of hydraulic jumps has been questioned in the light of empirical work and related literature on forced and smooth hydraulic jumps. At the final stage of the study, it was concluded that both strip and staggered roughness have positive effects on the characteristics of hydraulic jump given above. 3-7% more energy dissipation was observed in jumps on rough beds compared to classical hydraulic jumps. For tailwater dept reduction, whereas strip roughness provided 5-13%, staggered roughness led to 7-15% tailwater depth reduction compared to classical hydraulic jump. While strip roughness reduced jump length around 40%, 35-55% reduction was observed with staggered roughness when compared to classical hydraulic jump.

Subject Keywords

Hydraulic Engineering.

URI

http://etd.lib.metu.edu.tr/upload/12608038/index.pdf
https://hdl.handle.net/11511/16223

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

The effect of prismatic ruoghness elements on hydraulic jump Evcimen, Taylan Ulaş; Tokyay, Nuray; Department of Civil Engineering (2005) The objective of this study is to determine the effect of different roughness types and arrangements on hydraulic jump characteristics in a rectangular channel. Three different types of roughness were used along experiments. All of them had rectangular prism shapes and that were placed normal to the flow direction. To avoid cavitation, height of roughness elements were arranged according to level of the channel inlet, so that the crests of roughness elements would not be protruding into the flow. The effect...
Experimental investigation of energy dissipation through triangular screens Güngör, Endam; Bozkuş, Zafer; Department of Civil Engineering (2005) For the present study, a series of experimental works are executed to dissipate energy through triangular screens. Recent studies have shown that the implementation of the screen for energy dissipation is an effective way to extract out the excessive energy of water downstream of small hydraulic structures located in rivers of relatively negligible sediment content. In the present study, double screen arrangement with a porosity of 40% is used. The inclination angle of the screens is opted as 60 degree. The...
Discharge predictions using ann in sloping rectangular channels with free overfall Öztürk, Hayrullah Uğraş; Öztürk, Hayrullah Uğraş; Department of Civil Engineering (2005) In recent years, artificial neural networks (ANNs) have been applied to estimate in many areas of hydrology and hydraulic engineering. In this thesis, multilayered feedforward backpropagation algorithm was used to establish for the prediction of unit discharge q (m3/s/m) in a rectangular free overfall. Researchers̕ experimental data were used to train and validate the network with high reliability. First, an appropriate ANN model has been established by considering determination of hidden layer and node num...
Determination of hydraulic parameters of semi-infinite aquifers using Marquardt algorithm Taşkan, Cüneyt; Önder, Halil; Department of Civil Engineering (2004) In this study, transmissivity and storage coefficient of a semi-infinite, confined, homogeneous and isotropic aquifer, where the flow is one-dimensional and linear, are determined using Marquardt algorithm, considering two independent cases: constant drawdown in the adjacent stream; or constant discharge from the aquifer due to pumping at a constant rate. In the first case piezometric head and discharge measurements are utilized. Hydraulic diffusivity, which is the ratio of transmissivity to storage coeffic...
Investigation of critical submergence at single and multiple- horizontal intake structures having air- entraining vortices Gökmener, Serkan; Göğüş, Mustafa; Department of Civil Engineering (2015) In this experimental study the variation of the critical submergence of air- entraining vortices with important flow and geometrical parameters were investigated at single and multiple- horizontal intake structures. In the scope of this study, three identical pipes of diameter Di=0.265 m were tested at a wide range of discharge with varying side wall clearances under symmetrical and asymmetrical approach flow conditions. Using dimensional analysis dimensionless equation was developed for critical submergenc...

Citation Formats

Ç. Şimşek, “Forced hydraulic jump on artificially roughened beds,” M.S. - Master of Science, Middle East Technical University, 2006.