Sharif Digital Repository

Flapping wing vehicles produce aerodynamic lift and thrust through the flapping motion of their wings. The dynamic performance of a flexible membrane flapping wing is experimentally investigated here. To investigate aeroelastic effects of flexible wings (specifically, wing’s twisting stiffness) on hovering and cruising aerodynamic performance, a flapping-wing system and an experimental setup were designed and built. This system measures the unsteady aerodynamic and inertial forces, power usage and angular speed of the flapping wing motion for different flapping frequencies, angles of attack, various wind tunnel velocities up to 12 m/s and for various wings with different chordwise... 

Flapping wing vehicles produce aerodynamic forces through the flapping motion of their wings. A sample flapping wing mechanism is studied in this project, which propulsion system consists of a battery, a DC motor, a gearbox, a flapping mechanism and a flexible membrane wing. The purpose of this study is simulation of the whole propulsion system through identification and simulation of each sub-system. In the current research, after an introduction to the flapping wing vehicles, literature of the flapping vehicles is reviewed. By studying relevant articles, lack of a comprehensive simulation of all sub-systems is observed. So the goal of this research is obtaining an appropriate tool for... 

Flapping is one of the most usual solutions to produce aerodynamic lift and propulsive force in natural flights, in low Reynolds number. A sample flapping wing mechanism in which propulsion system consists of a battery, two very small DC electrical motors, two gearboxes, a flapping mechanism and flexible beams as wings is studied in this project.Different methods have been proposed to derive the governing equations of motion and simulate the flapping wing system. The main disadvantage of the previous proposed works is the lack of a comprehensive dynamical analysis of the complete system including its components.Therefore, the main objective of the present research is to propose an efficient... 

In adaptation with nature, Flapping Wing Arial Robots (FWARs) are flying vehicles that use wing flapping motion to produce lift and thrust forces simultaneously. Wing oscillating motion of FWARs in turn creates an unsteady and turbulent flow field around them that makes their aerodynamic modeling and analysis a complex and formidable task. As a result, experimental aerodynamic investigation of FWARs has been the focus of many researchers in the last few years. Inspired by nature, Bird-like FWARs utilize a tail as an augmented aerodynamic surface during their flight motion. In turn the tail aerodynamics that in general plays an important role in flight stability and control is adversely... 

Radial inflow gas turbines are widely used in auxiliary power units, small industrial gas turbines and turbocharger of internal combustion engines. They have advantage for low mass flow rate and wide range operation conditions. This research aimed to improve aerodynamic performance of the radial turbine of GT4082 Garret turbocharger. First, performance characteristics of the turbine were obtained experimentally at Turbocharger Laboratory of Sharif University of Technology. Laboratory results are the basis for modeling evaluation. Then, a one-dimensional model was developed to predict the turbine performance characteristics. The model results were compared with experimental results, that...