Loading...
Search for:
vortex-interaction
0.009 seconds
Experimental Investigation of the Effects of Wing Aspect ratio and its distance from the Tail on the Aerodynamic parameters at high A.O.A
, M.Sc. Thesis Sharif University of Technology ; Soltani, Mohammad Reza (Supervisor) ; Hejranfar, Kazem (Supervisor)
Abstract
In recent years, requirement to increase projectile performance, leads to a great interest in high angle of attack Aerodynamics. Projectile Maneuverability is a concept which is defined by having the capability to perform at high angles of attack while maintaining attached flow over the tail, rather than a capability of performing a mission in minimum possible duration. Interaction between body, wing and tail vortices can delay vortex breakdown over the wing and as a result may enhance projectile maneuverability. Studies show that wing aspect ratio and tail location have a remarkable influence on the vortices interaction and thus projectile maneuverability. In the present study, a series of...
Vortex shedding modes around oscillating non-uniform double heave plates
, Article Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment ; 2020 ; Alvandi, M ; Behzad, M ; Thiagarajan, K. P ; Sharif University of Technology
SAGE Publications Ltd
2020
Abstract
Multiple co-axial heave plates of uniform geometry are attached to offshore platforms for inducing damping and added mass. These effects generally decrease the magnitude of the dynamic response of the platform under applied environmental excitation forces. When spacing between heave plates is decreased the damping and added mass performance are altered due to their strong vortex interaction. A new non-uniform plate configuration is proposed that may create different hydrodynamic characteristics. The modes of vortex shedding around plate edges in a non-uniform arrangement under forced harmonic oscillation are investigated via the CFD method. Furthermore, a new simplified formula for the total...
Vortex Shedding Control behind Helicopter Rotor Blades, using Thin Oscillating Plates- Application to Helicopter Noise Reduction
, M.Sc. Thesis Sharif University of Technology ; Javadi, Khodayar (Supervisor)
Abstract
The interaction of the vortices and helicopter’s blades is the most significant source of generating the main rotor’s noise, especially in landing and rising. The kind of this noise is broadband and it is produced because of establishing the vortices behind the forward blade, their interaction with backward blade, changing their structures and creating turbulency loading. The known method for modeling of the interaction of the vortices structures and solid surfaces is the simple compounding the rod and airfoil. In this project, by using this method, the noise of the interaction of vortex and blade is modeled in the Reynolds number of 48000 with LES and FW-H Analogy as a hibrid method in...
Energy Extraction from Two Oscillating Airfoils in Tandem Configuration at Low-Reynolds-number Turbulent Flow
, M.Sc. Thesis Sharif University of Technology ; Ebrahimi, Abbas (Supervisor)
Abstract
In this study, the physic of an unsteady flow surrounding two oscillating airfoils in tandem configuration at low Reynolds-numbers has been simulated in a 2D manner by utilizing the Sliding-mesh approach and K-ω-SST turbulent model in Ansys-Fluent application. The first step in this study is selecting the decent numerical grid and flow solution scheme. After choosing the proper solution for this problem, next is to verify the methodology with respect to the references. In the next step, The tandem configuration and pitching motion of the airfoils is being implemented with existing tools and the flow structure, leading-edge and trailing-edge vortex shedding and blade-vortex interactions is...
Harvesting of Aquatic Clean Energy from Vortex Induced Vibration Using Two Degree Of Freedom Cylindrical Oscillator and Piezoelectric
, M.Sc. Thesis Sharif University of Technology ; Raie, Mohammad (Supervisor)
Abstract
Vortex-induced vibration is a known phenomenon in fluids flow that is being studied in different fields of engineering and usually, we want to reduce the harmful effects of this phenomenon on the subjected structures. Also, it is possible to use this phenomenon for harvesting clean energy from fluids flow. Energy harvesting from vortex-induced vibrations is based on the maximizing of flow instead of its reduction, and the utilization of these vibrations instead of their suppression. Vortex induced vibrations occur in any ranges of Reynolds numbers. Only in three transient regions cause a reduction in vortex-induced vibrations; therefore, even in streams with a velocity less than 0.2 m/s, it...
A broad reconsideration of anti-vortex film cooling method using numerical optimization and an improved heat-flux model
, Article International Journal of Heat and Fluid Flow ; Volume 89 , 2021 ; 0142727X (ISSN) ; Mazaheri, K ; Sharif University of Technology
Elsevier B.V
2021
Abstract
This paper represents the detailed results of an evolutionary optimization framework towards the exploration of vortex mechanisms leading to effective anti-vortex film cooling. In this regards, several arrangements of triple cooling holes were studied on flat and curved geometries using differential-evolution optimization algorithm and a modified Reynolds-stress based flow solver. Depending on the flow and geometric parameters, four distinct types of vortex interaction with different cooling mechanisms were identified. The vortex-trapping mechanism, observed in the optimized upstream arrangement acts through imposing a mild downwash over the main counter-rotating vortex pair and provides the...
Vortex shedding modes around oscillating non-uniform double heave plates
, Article Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment ; Volume 235, Issue 2 , 2021 , Pages 558-569 ; 14750902 (ISSN) ; Alvandi, M ; Behzad, M ; Thiagarajan, K. P ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Multiple co-axial heave plates of uniform geometry are attached to offshore platforms for inducing damping and added mass. These effects generally decrease the magnitude of the dynamic response of the platform under applied environmental excitation forces. When spacing between heave plates is decreased the damping and added mass performance are altered due to their strong vortex interaction. A new non-uniform plate configuration is proposed that may create different hydrodynamic characteristics. The modes of vortex shedding around plate edges in a non-uniform arrangement under forced harmonic oscillation are investigated via the CFD method. Furthermore, a new simplified formula for the total...
Vortex shedding modes around oscillating non-uniform double heave plates
, Article Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment ; Volume 235, Issue 2 , 2021 , Pages 558-569 ; 14750902 (ISSN) ; Alvandi, M ; Behzad, M ; Thiagarajan, K. P ; Sharif University of Technology
SAGE Publications Ltd
2021
Abstract
Multiple co-axial heave plates of uniform geometry are attached to offshore platforms for inducing damping and added mass. These effects generally decrease the magnitude of the dynamic response of the platform under applied environmental excitation forces. When spacing between heave plates is decreased the damping and added mass performance are altered due to their strong vortex interaction. A new non-uniform plate configuration is proposed that may create different hydrodynamic characteristics. The modes of vortex shedding around plate edges in a non-uniform arrangement under forced harmonic oscillation are investigated via the CFD method. Furthermore, a new simplified formula for the total...