Numerical study of turbulent flow over an S-shaped hydrofoil
01 Sep 2008-Vol. 222, Iss: 9, pp 1717-1734
TL;DR: In this paper, a numerical study of turbulent flow over the S-shaped hydrofoil at 0° angle of attack has been reported, where the flow takes place over concave and convex surfaces and is accompanied by the favorable and adverse pressure gradients and flow separation.
Abstract: In this paper, a numerical study of turbulent flow over the S-shaped hydrofoil at 0° angle of attack has been reported. Here, the flow takes place over concave and convex surfaces and is accompanied by the favourable and adverse pressure gradients and flow separation. Modelling such a flow poses a formidable challenge. In the present work four turbulence models, namely, k–∊ realizable, k–ω shear stress transport
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TL;DR: In this article, a new duct is developed for a given turbine design, that reduces the variation in torque over a cycle by appropriately directing the flow upstream and downstream the turbine while increasing power conversion.
60 citations
11 May 2011
TL;DR: The efficiency of jet pump is poor and it usually has a sharp peak in the efficiency-discharge ratio curve as mentioned in this paper, which is undesirable for the purpose of transporting materials in the air.
Abstract: Jet pump plays a major role in transporting materials. The efficiency of jet pump is poor and it usually has a sharp peak in the efficiency–discharge ratio curve. These are undesirable. In the past...
17 citations
TL;DR: In this paper, a numerical investigation of flow over a cascade of S-shaped hydrofoils is presented, and it is found from numerical simulations that the useful range of operation is restricted to 6° for turbine operation and −6° for pump operation.
12 citations
01 Oct 2009
TL;DR: In this article, the effects of convex wall curvature on turbulent boundary layer flow were studied using a numerical method using the non-linear k−e model often used in engineering applications.
Abstract: Effects of convex wall curvature on turbulent boundary layer flow are studied in this article using a numerical method. Since the non-linear k−e model often used in engineering applications...
5 citations
References
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TL;DR: In this article, a specially designed directionally sensitive laser anemometer was constructed and used to make measurements in the separated region of a separating turbulent boundary layer, and cross-wire hotwire measurements were obtained upstream of separation and in the outer region of the separated flow.
Abstract: Simpson, Chew & Shivaprasad (1981 a , b) describe many experimentally determined features of a separating turbulent boundary layer. For the same flow, experimental results for the transverse velocity component are presented here. A specially designed directionally sensitive laser anemometer was constructed and used to make measurements in the separated region. Cross-wire hot-wire anemometer measurements were obtained upstream of separation and in the outer region of the separated flow and are in good agreement with the laser anemometer results. It was found that wI2 = v t2 in the outer 90 yo of the shear layer both upstream and downstream of separation. Features of wI2 profiles in the backflow are related to features of the streamwise velocity component. This behaviour is consistent with the large-scale-structures flow model of a separating boundary layer presented by Simpson et al. (1981a, b ) . Large-scale structures supply the mean streamwise backflow. These large-scale structures also transport the turbulence energy to the backflow from the outer flow by turbulent diffusion since advection and production of turbulence kinetic energy are negligible there compared with the dissipation rate. Because of continuity requirements fluid motions toward the wall must be deflected and contribute to streamwise and transverse motions near the wall.
55 citations
TL;DR: In this paper, the effects of strong convex and concave curvature on turbulent duct flows are investigated using a compressible Navier-Stokes code incorporating Reynolds stress models using a four-stage Runge-Kutta scheme.
Abstract: The effects of strong convex and concave curvature on turbulent duct flows are investigated. A compressible Navier-Stokes code incorporating Reynolds stress models has been developed using a four-stage Runge-Kutta scheme. Numerical computations have been carried out for strongly curved 180-deg turnaround duct flows with a Reynolds stress model, an algebraic Reynolds stress model, and a nonlinear κ-e model. A detailed assessment of the models' capability in predicting the effects of strong streamline curvature has been carried out. The effect of curvature parameter δ/R on the development of mean flow and turbulence has been examined by numerical simulations with the Reynolds stress model.
52 citations
TL;DR: Some aspects of the foundation and application of turbulence models to flows that relate to aeronautical practice are reviewed, with particular emphasis being placed on turbulence-transport models at a closure level higher than that based on the Boussinesq-viscosity hypothesis.
46 citations
TL;DR: In this paper, the changes in turbulence in a flow over a two-dimensional curved hill, described in Part 1 (Baskaran, Smits & Joubert 1987), were analyzed in the light of transport equations for the turbulent kinetic energy.
Abstract: The changes in turbulence in a flow over a two-dimensional curved hill, described in Part 1 (Baskaran, Smits & Joubert 1987), are analysed in the light of transport equations for the turbulent kinetic energy, . The transport terms are found to be affected by streamline curvature. To the thin shear layer approximation, the interaction between streamline curvature and streamwise pressure gradient appears to be weak.
46 citations
TL;DR: A second-moment Reynolds stress transport model (RSTM) is used in this article for computing the flow around a two-dimensional airfoil, employing a non-staggered grid arrangement.
Abstract: A second-moment Reynolds Stress Transport Model (RSTM) is used in the present work for computing the flow around a two-dimensional airfoil. An incompressible SIMPLEC code is used, employing a non-staggered grid arrangement. A third-order QUICK scheme is used for the momentum equations, and a second-order, bounded MUSCL scheme is used for the turbulent quantities. As the RSTM is valid only for fully turbulent flow, an eddy viscosity, one-equation model is used near the wall. The two models are matched along a preselected grid line in the fully turbulent region. Detailed comparisons between calculations and experiments are presented for an angle of attack of α = 13.3 deg. The RSTM predictions agree well with the experiments, and approaching stall is predicted for α = 17 deg, which agrees well with experimental data. The results obtained with a two-layer k − e model show poor agreement with experimental data; the velocity profiles on the suction side of the airfoil show no tendency of separation, and no tendency of stall is predicted
27 citations