Showing 2 results for Keshavarzi
A. Keshavarzi and M. J. Kazemzadeh Parsee,
Volume 24, Issue 1 (7-2005)
Abstract
Flow separation at water intake is the main cause of head loss and flow discharge reduction.
As a result, study of shape and size of separation is very essential when designing an optimum water intake. Water intake is normally built with a 90 degree angle to the main channel flow direction. However, the flow structure in this type of water intake consists of large separation size along with vortex generation. In this study, the effect of the ratio of discharge at water intake to the main channel discharge (Qr) on the location and size of separation is investigated numerically and experimentally. The velocity of the flow at each point is measured in two dimensions using electromagnetic velocity meter. The results from the experimental data indicate that the location and shape of separations are a function of flow discharge ratio (Qr). These results also indicate that at higher ratios of flow discharge, the separation occurs downstream the water intake, whereas at lower flow discharges, the flow separation occurs upstream the water intake. Additionally, the capabilites of numerical turbulence computation models including standard k-e and RNG k-e models are investigated in this study. The computed flow velocity from the turbulence models showed that the result of standard k-e model is approximately close to the experimental data when compared with RNG k-e model
R. Keshavarzi, Sh. Hatami, Sh. Hashemi,
Volume 39, Issue 2 (2-2021)
Abstract
Plates made of laminated composite materials with variable stiffness can have wide applications in various branches of engineering due to such advantages as high strength /stiffness to weight ratio. In these composites, curved fibers are used to reinforce each lamina instead of the straight fibers. In this paper, the application of finite strip method for the buckling analysis of moderately thick composite plates with variable stiffness is investigated. For buckling analysis, a semi-analytical finite strip method based on the first-order shear deformation theory is employed. In this method, all displacements are presumed by the appropriate harmonic shape functions in the longitudinal direction and polynomial interpolation functions in the transverse direction. The minimum potential energy method has been used to develop the stability formulations. This analysis examines the effect of using curved fibers instead of straight fibers on the laminate composites. The critical loads obtained from this analysis are compared with those of other researchers and the efficiency and accuracy of the developed finite strip method are confirmed. Comparison of the analysis results of these plates shows that changing the slope of the fibers can lead to a significant change in the buckling response. Also, increasing the number of the terms of shape functions in the longitudinal direction has a significant effect on the convergence to the desired results.
