Local energy losses at positive and negative steps in subcritical open channel flows

Download
2011-01-01
Local energy losses occur when there is a transition in open channel flow. Even though local losses in subcritical open channel flow due to changes in channel width have been studied, to date no studies have been reported for losses due to changes in bed elevations. Steps are commonly used in engineering applications to stabilise the flow in open channels. Hence, it is important to estimate local losses for design purposes. The aim of this study was to formulate the local energy losses at positive and negative steps in subcritical open channel flows. Flow rates and water depths before and after the step were measured for varying step heights of abrupt and 45o inclined steps. Empirical equations relating the local losses to the Froude number on the step and the relative step height are proposed for positive and negative steps. In addition, practical values of local loss coefficients are determined.

Suggestions

Ensemble Modeling of Hydrologic and Hydraulic Processes at One Shot: Application to Kinematic Open-Channel Flow under Uncertain Channel Properties and Uncertain Lateral Flow Conditions by the Stochastic Method of Characteristics
Ercan, Ali; Kavvas, M. L. (2012-03-01)
A stochastic kinematic wave model for open channel flow is developed under uncertain channel properties and uncertain lateral flow conditions. Applying a known methodology, the Fokker-Planck equation (FPE) of the kinematic open-channel flow process under uncertain channel properties and uncertain lateral flow conditions is derived using the method of characteristics. Because every stochastic partial differential equation has a one-to-one relationship with a nonlocal Lagrangian-Eulerian Fokker-Planck equatio...
NUMERICAL STABILITY OF RBF APPROXIMATION FOR UNSTEADY MHD FLOW EQUATIONS
Gurbuz, Merve; Tezer, Münevver (2019-01-01)
In this study, the radial basis function (RBF) approximation is applied for solving the unsteady fluid flow and magnetohydrodynamic (MHD) convection flow problems with the use of explicit Euler time discretization and relaxation parameters to accelerate the convergence. The stability analysis is also carried out in terms of the spectral radius of related RBF discretized coefficient matrices. The optimal choices of the time increment, relaxation parameters and physical problem parameters are found for achiev...
Dynamic modelling and simulation of a wind turbine
Altuğ, Ayşe Hazal; Yavrucuk, İlkay; Department of Aerospace Engineering (2015)
In this thesis, a dynamic model for a horizontal axis wind turbine is developed for an upwind configuration using the MATLAB/Simulink environment. Blade Element Momentum Theory is used to model the rotor. It is assumed that the rotor blades are rigid and wind speed is uniform. Aerodynamic and gravitational forces are calculated as distributed loads. Verification of the model is done by using the LMS Samtech, Samcef for Wind Turbines software. Aerodynamic properties of the blades, sectional loads and moments...
Ensemble Modeling of Hydrologic and Hydraulic Processes at One Shot: Application to Kinematic Open-Channel Flow under Uncertain Channel Properties by the Stochastic Method of Characteristics
Ercan, Ali; Kavvas, M. L. (2012-01-01)
A stochastic kinematic wave model for open-channel flow under uncertain channel properties is developed. The Fokker-Planck equation (FPE) of the kinematic open-channel flow process under uncertain channel properties is developed by using the method of characteristics. Every stochastic partial differential equation has a one-to-one relationship with a nonlocal Lagrangian-Eulerian FPE (LEFPE). As such, one can develop an LEFPE for the governing equation of any hydrologic or hydraulic process as the physically...
Numerical solution of buoyancy MHD flow with magnetic potential
Pekmen, B.; Tezer, Münevver (2014-04-01)
In this study, dual reciprocity boundary element method (DRBEM) is applied for solving the unsteady flow of a viscous, incompressible, electrically conducting fluid in channels under the effect of an externally applied magnetic field and buoyancy force. Magnetohydrodynamics (MHD) equations are coupled with the energy equation due to the heat transfer by means of the Boussinessq approximation. Then, the 20 non-dimensional full MHD equations in terms of stream function, temperature, magnetic potential, curren...
Citation Formats
N. Tokyay and A. B. Altan Sakarya, “Local energy losses at positive and negative steps in subcritical open channel flows,” Water SA, pp. 237–244, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/29959.