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Experimental Investigation of Aerodynamic Performance Enhancement by Trailing Edge Active Flow Control Using Plasma Actuator
,
M.Sc. Thesis
Sharif University of Technology
;
Ebrahimi, Abbas
(Supervisor)
Abstract
Flow control means changing the optimal flow behavior of the fluid in accordance with the desired targets, such as decreasing drag force, increasing the lift force or lift to drag ration, as well as manipulating the separation of the flow from the surface. So far, little research has been done on increasing the airflow performance through the active control of the trailing edge flow. Gurney flap is a great tool, and its experimental results show a significant increase lift force in the airfoil. In this study, it is possible experimentally to use plasma actuators to create microtap and garney flap artificial for enhancing the aerodynamic performance of airfoil by controlling the flow field at...
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...
Numerical Investigation of Cavity Control with Utilization of Artificial Cavity Generator
, M.Sc. Thesis Sharif University of Technology ; Javadi, Khodayar (Supervisor)
Abstract
Cavitation is a phenomenon that liquid turns into vapor in constant temperature. Cavitation has been assorted into variant models that cloud cavitation is one of them. Cloud cavitation has an unsteady regime which shed cavity into its surrounding that contribute to oscillations, shocks and efficiency reduction of hydrodynamic machines. Triping of boundary layer for enhancing turbulent intensity is a method for preventing cloud cavitation. In this thesis firstly we have simulated boundary layer on 2D NACA0015 hydrofoil with 8 degree attack angle and no cav( ) condition. According to laminar separation location, we have placed some artificial cavity generator(ACG) with size of boundary layer...
The Multi-Depot Traveling Purchaser Problem with Shared Resources
, Ph.D. Dissertation Sharif University of Technology ; Ebrahimi, Abbas (Supervisor)
Abstract
Increasing the kinetic energy of the near-wall fluid by exciting shear layers is known as an effective method for flow separation control. So far, choosing the proper approach to apply excitations has been a challenging issue in the field of flow control. This work investigates flow control of airfoils in static stall and flutter conditions, employing shear layer excitation technique and plasma actuators. This research introduces a novel flow separation control, namely dual-point excitation of shear layers and compares its performance with the conventional single-point excitation method. Two airfoils (NACA 4415 and NACA 0015) have been considered as the baseline test-cases. In the first part...
Unsteady multiphase modeling of cavitation around NACA 0015
, Article Journal of Marine Science and Technology ; Volume 18, Issue 5 , 2010 , Pages 689-696 ; 10232796 (ISSN) ; Jahanbakhsh, E ; Seif, M. S ; Sharif University of Technology
Abstract
The present study focuses on the numerical simulation of cavitation around the NACA 0015. The unsteady behaviors of cavitation which have worthwhile applications are investigated. The cavitation patterns, velocity fields and frequency of the cavitating flow around hydrofoil is obtained. For multi phase simulation, single-fluid Navier-Stokes equations, along with a volume fraction transport equation, are employed. The bubble dynamics model is utilized to simulate phase change. SIMPLE algorithm is used for velocity and pressure computations. For discretization of equations the finite-volume approach written in body fitted curvilinear coordinates, on collocated grid, is used. In this study,...