Loading...
Search for:
tip-vortex
0.004 seconds
Experimental Study of the Pressure Distribution on the Surface of an Infinite Wing Influenced by Different Sweep Angles
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor)
Abstract
A series of wind tunnel tests were performed to examine the effects of wing sweep and wing tip vortices on the pressure distribution of the upper surface of three wings with sweep angles of 23,33 and 40 degrees. The wing section had a laminar flow airfoil similar to that of NACA 6-series airfoils. All tests, were conducted at a chord Reynolds number of 8×〖10〗^5, and for a range of angle of attack -2 to14 degree. Generation of Wing tip vortices are eliminated by placing an End-plate on the wing tip. Static pressure distributions over the upper surface of the wing at three chordwise direction and at one spanwise direction along the quarter chord line are obtained. The results show that the...
Numerical and Experimental Study of Induced Drag Reduction Using a Wing Grid at Low Reynolds Numbers
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohamad Reza (Supervisor) ; Banazadeh, Afshin (Supervisor) ; Farahani, Mohammad (Co-Supervisor)
Abstract
Wing grids are among devices used for increasing wing performance. Wing grids decrease wing induced drag by breaking the wing main tip vortex to smaller vortices with lower turbulence intensity value. These devices are mostly used in low Reynolds regimes, and their effectiveness decreases as the Reynolds number increases. In most researches around the world, wing grids have simple design configurations, but in this research wing grids are designed in such a way that each grid has a minimum value of induced drag respectively. So, in addition to reducing baseline wing induced drag by breaking the main vortex to smaller vortices by means of wing grid, each grid has a minimum value of induced...
Effects of boundary layer control method on hydrodynamic characteristics and tip vortex creation of a hydrofoil
, Article Polish Maritime Research ; Volume 24, Issue 2 , 2017 , Pages 27-39 ; 12332585 (ISSN) ; Tanha, A ; Kourabbasloo, N. N ; Tavakoli, S ; Sharif University of Technology
De Gruyter Open Ltd
2017
Abstract
There is currently a significant focus on using boundary layer control (BLC) approach for controlling the flow around bodies, especially the foil sections. In marine engineering this is done with the hope of increasing the lift - to - drag ratio and efficiency of the hydrofoils. In this paper, effects of the method on hydrodynamic characteristics and tip vortex formation of a hydrofoil are studied. Steady water injection at the tip of the hydrofoil is simulated in different conditions by using ANSYS-CFX commercial software. Validity of the proposed simulations is verified by comparing the obtained results against available experimental data. Effects of the injection on the lift, drag, and...
An improved Mesh Adaption and Refinement approach to Cavitation Simulation (MARCS) of propellers
, Article Ocean Engineering ; Volume 171 , 2019 , Pages 139-150 ; 00298018 (ISSN) ; Atlar, M ; Khorasanchi, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This paper presents the improvements of cavitation modelling for marine propellers particularly developing tip vortex cavitation. The main purpose of the study is to devise a new approach for modelling tip vortex cavitation using Computational Fluid Dynamics (CFD) methods with commercial software, STAR-CCM+. The INSEAN E779A model propeller was used for this study as a benchmark propeller. Utilizing this propeller, firstly, validation studies were conducted in non-cavitating conditions together with grid and time step uncertainty studies. Then, the cavitation was simulated on the propeller using a numerical cavitation model, which is known as the Schnerr–Sauer model, based on the...
Effects of wing geometry on wing-body-tail interference in subsonic flow
, Article Scientia Iranica ; Volume 18, Issue 3 B , 2011 , Pages 407-415 ; 10263098 (ISSN) ; Soltani, M. R ; Askari, F ; Pajuhande, H. R ; Sharif University of Technology
Abstract
Extensive wind tunnel tests were performed on several wing- body-tail combinations in subsonic flow to study the effects of wing geometric parameters on the flow field over the tail. For each configuration, tail surface pressure distribution, as well as the velocity contour at a plane perpendicular to the flow direction behind the wing was measured. The results show a strong effect of wing to tail span ratio, as well as wing aspect ratio, on the flowfield downstream of the wing. For low sweep wings, as those considered here, wing and body interference effects on the tail are associated with the wing tip vortex and nose-body vortex