Numerical Investigation of Non-Stationary Parameters on Effective Phenomena of a Pitching Airfoil at Low Reynolds Number

Abstract

Various applications of ornithopter have led to research interest in oscillation airfoils which affect on low Reynolds number flight, like; pitching oscillation, heaving oscillation and flapping of a wing. The purpose of this study is investigation of aerodynamic characteristics of NACA0012 airfoil with a simple harmonic pitching oscillation at zero and 10 degrees of mean angle of attack. Therefore the effects of unstable parameters, including oscillation amplitude up to 10 degrees, reduced frequency up to 1.0, center of oscillation up to 6/8 chord length, and Reynolds number up to 5000 have been studied numerically. A pressure based algorithm using a finite volume element method has been used to solve Navier-Stokes equations. According to results, variation of each studied parameters at mean angle of attack of 0 degree do not cause significant changes in flow phenomena on airfoil but at mean angle of attack of 10 degrees, changing in reduced frequency and specially Reynolds number cause variations in flow phenomena. These variations are because of "wake capturing" and/or "added mass" phenomena.

Investigation of Corrugated Wing in Unsteady Motion

“…The Reynoldsnumber is chosen since this Re range has been used in many studies for MAVs such as by Naderi et al 2016).Typical applications of MAV include search and rescue operations, situational awareness in battlefield, aerial surveillance and reconnaissance, sensing biological and chemical agents, sports broadcasting and many more. Tamai and H.Hu (2008) have conducted an experimental study on the bioinspired airfoil at the Re 34000 and compared it with the GA(W)-1 airfoil and the flat plate with an aim to explore the potential applications of such untraditional airfoils in the MAV design.…”

Dynamic Stall Prediction of a Pitching Airfoil using an Adjusted Two-Equation URANS Turbulence Model

“…The commercial software package ANSYS Fluent 13.0 was used in this computation. Two dimensional analysis was selected because it is quite useful for observation of the flow characteristics and it can be useful in predicting the aerodynamic dependency of various parameters (Naderi et al 2016). The SIMPLE algorithm was applied in the pressure velocity coupling and all equations to obtain a simultaneous solution (Wang et al 2010).…”

“…Many studies have been conducted to reveal the dynamic stall mechanism (Bangga and Sasongko 2012;Naderi et al 2016). Until the middle of 20th century, the dynamic stall was only studied experimentally due to limitation of the background data to govern the mathematical formulations.…”

Force Generation Mechanisms by an Insect Wing in Hovering Motion with Different Flipping Schedules

“…The results provide a useful insights into the mechanism of the unsteady force generation during the hovering at Re=4000. The Reynolds number is chosen since this Re range has been used in many studies for MAVs such as by A Naderi et al (2016). It is pertinent to mention that Re=4000 is selected on the premise that the length scale (mean aerodynamic chord) becomes closer to a Micro Air Vehicle (MAV).…”