compressible gas flow inside a convergent-divergent nozzle and its exhaust plume atdifferent nozzle pressure ratios (npr) have been numerically studied with severalturbulence models. the numerical results reveal that, the sst k–ω model give the bestresults compared with other models in time and accuracy. the effect of changes in value ofdivergence half-angle (ε ) on the nozzle performance, thru...

one of the causes of perturbation at vertical intakes is the happening of vortices with an air core. the vortices with an air core occur whenever the submergence of the intake is less than a critical value. anti-vortex devices and specially plates are used to avoid the negative effects of the air-core vortices. if plates are used, then the geometry of them should be studied experimentally. acco...

The piano key weir (PKW) is a type of nonlinear control structure that can be used to increase unit discharge over linear overflow weir geometries, particularly when the weir footprint area is restricted To predict the outflow passing over a piano key weir, the discharge coefficient in the general equation of weir needs to be known. This paper presents the results of laboratory model testing of...

in this paper twelve different empirical resistance coefficients expressed in terms of manning's roughness are used apiece in seventeen known compositing methods. the data obtained from ten different cross-sections of the sefidrood river, iran, are used for the evaluation of the empiricalformulas. the present case-study is selected from a reach with gravel bed topology. then no remarkable bed f...

different construction materials with different roughness used to make circular weirs highly affect surface roughness and, in turn, flow hydraulics passing over these structures.  in the present research, numerous experiments under different hydraulic conditions were performed on a physical model to study the effects of roughness on flow hydraulics over a circular weir. the flow hydraulics incl...

Weirs have widely been used for the flow measurement, flow diversion and its control in the open channels. Attempts have been made to study flow over different shapes of normal weirs, side weirs and oblique weirs. This paper is connected with the development of the discharge coefficient measurement. In the present study four different weirs in different height are considered for validation purp...

One of the causes of perturbation at vertical intakes is the happening of vortices with an air core. The vortices with an air core occur whenever the submergence of the intake is less than a critical value. Anti-vortex devices and specially plates are used to avoid the negative effects of the air-core vortices. If plates are used, then the geometry of them should be studied experimentally. Acco...

A computational analysis of flow in simplex fuel atomizers using the arbitrary-Lagrangian–Eulerian method is presented. It is well established that the geometry of an atomizer plays an important role in governing its performance. We have investigated the effect on atomizer performance of four geometric parameters, namely, inlet slot angle, spin chamber convergence angle, trumpet angle, and trum...

long-throated flumes are measurement structures often used in water and wastewater systems to determine the flow discharge. the head-discharge relationship of long-throated flumes is traditionally determined following the critical flow theory and the boundary layer concept. after a review of the traditional approach and an analysis of the approximate assumptions of the boundary layer approach, ...