نتایج جستجو برای: Flapping

تعداد نتایج: 1873  

Today, Flapping Micro Aerial Vehicles (MAV) are used in many different applications. Reynolds Number for this kind of aerial vehicle is about 104 ~ 105 which shows dominancy of inertial effects in comparison of viscous effects in flow field except adjacent of the solid boundaries. Due to periodic flapping stroke, fluid flow is unsteady. In addition, these creatures have some complexities in kin...

2012
LAN LIU XIJING ZHANG ZHAOXIA HE

A lightweight flapping-wing micro air vehicle (MAV) was designed and built and successfully filed in the sky. The unsteady aerodynamics associated with this MAV was detailedly studied by using the method of computational fluid dynamics (CFD).The variations of different parameters of the flapping MAV, such as flapping amplitude, pitch amplitude and flapping frequency, were investigated with nume...

2016
Gottfried Sachs

The power required by flapping and fixed wing vehicles in level flight is determined and compared. Based on a new modelling approach, the effects of flapping on the induced drag in flapping wing vehicles are mathematically described. It is shown that flapping causes a significant increase in the induced drag when compared with a non-flapping, fixed wing vehicle. There are two effects for that i...

2006
David J. Willis Jaime Peraire Mark Drela K. White

A computational framework for analyzing and designing efficient flapping flight vehicles is presented. Two computational tools are considered: a Betz Criterion code proposed by Hall et. al., and an accelerated, unsteady, potential flow solver. The parameters considered in this paper are: the flapping frequency, the flapping amplitude in both up-down and forward-aft directions, and the addition ...

2007
Beerinder Singh Inderjit Chopra Balakumar Balachandran

Title of dissertation: DYNAMICS AND AEROELASTICITY OF HOVER CAPABLE FLAPPING WINGS: EXPERIMENTS AND ANALYSIS Beerinder Singh, Doctor of Philosophy, 2006 Dissertation directed by: Professor Inderjit Chopra Department of Aerospace Engineering This dissertation addresses the aerodynamics of insect-based, bio-inspired, flapping wings in hover. An experimental apparatus, with a bio-inspired flapping...

Journal: :Bioinspiration & biomimetics 2014
Loïc Was Eric Lauga

Swimming fish and flying insects use the flapping of fins and wings to generate thrust. In contrast, microscopic organisms typically deform their appendages in a wavelike fashion. Since a flapping motion with two degrees of freedom is able, in theory, to produce net forces from a time-periodic actuation at all Reynolds numbers, we compute in this paper the optimal flapping kinematics of a rigid...

Journal: :The Journal of experimental biology 1995
Tobalske

Electromyographic (EMG) and kinematic data were collected from European starlings (Sturnus vulgaris) flying at a range of speeds from 8 to 18 m s-1 in a variable-speed windtunnel. Their flight at all speeds consisted of alternating flapping and non-flapping phases. Wing postures during non-flapping phases included glides, partial-bounds and bounds. Glides were performed proportionally more ofte...

2013
Perumal Manimekalai

Recently, flapping robots are noticed by many researchers, and many challenges are being made toward the realization of flight motions like insects, birds and so on. The purpose of this work is to develop flapping robots using a new type of piezoelectric material, that is, piezoelectric fiber composites. By using the composites, actuating fibers and sensing fibers can be embedded into a wing as...

2010
Jae-Hung Han

The flapping wing flight has superior maneuverability and aerodynamic advantages in a low Reynolds number regime. Nature’s flyers generate aerodynamic forces and moments from the various wing motions such as flapping and pitching to fly and sustain its flight stability. Bioinspired design of flapping air vehicle is one of the effective ways to exploit such a complex system. However the flapping...

Journal: :Integrative and comparative biology 2002
Jeffrey A Walker

Why do some animals swim by rowing appendages back and forth while others fly by flapping them up and down? One hypothesis suggests the answer lies in the sharply divergent physical environments encountered by small, slow animals, and large, fast animals. Flapping appendages allow large animals to move through a fluid environment quickly and efficiently. As size and speed decrease, however, vis...

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