The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform
Rick Lind - One of the best experts on this subject based on the ideXlab platform.
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Time-varying dynamics of a micro air vehicle with variable-Sweep morphing
Journal of Guidance Control and Dynamics, 2012Co-Authors: Animesh Chakravarthy, Daniel Grant, Rick LindAbstract:In this paper, we investigate the dynamics of a rapidly morphing, variable Wing Sweep micro air vehicle. The time scales over which the morphing occurs are of the same order as those of the flight dynamics of the MAV. We investigate the time-varying poles and zeros of this MAV for different morphing trajectories. There are several existing notions of timevarying poles and zeros of a linear time-varying system, each with its relative advantages and disadvantages. We explore the use of two of these notions in the study of the timevarying dynamics of the MAV in both the longitudinal as well as the lateral-directional axes.
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flight dynamics of a morphing aircraft utilizing independent multiple joint Wing Sweep
International Journal of Micro Air Vehicles, 2010Co-Authors: Daniel Grant, Mujahid Abdulrahim, Rick LindAbstract:Morphing, which changes the shape and configuration of an aircraft, is being adopted to expand mission capabilities of aircraft. The introduction of biologically-inspired morphing is particularly attractive in that highly-agile birds present examples of aerodynamically-effective shapes. This paper introduces an aircraft with a multiple-joint design that allows variations in Sweep to mimic some shapes observed in birds. These variations are independent on the left and right Wings along with on the inboard and outboard sections. The aircraft is designed and analyzed to demonstrate the range of flight dynamics which result from the morphing. In particular, the vehicle is shown to have enhanced turning capabilities and crosswind rejection which are certainly critical metrics for the urban environments in which these aircraft are anticipated to operate.
Kim Wright - One of the best experts on this subject based on the ideXlab platform.
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Investigating the use of Wing Sweep for pitch control of a small unmanned air vehicle
2011Co-Authors: Kim WrightAbstract:Small Unmanned Air Vehicles (UAVs) are versatile tools with both civilian and military applications. Fixed Wing UAVs require forward airspeed to remain airborne, usually resulting in constant energy expenditure to loiter over targets. A UAV capable of perching could reduce energy expenditure by settling on a site near the target, thus increasing mission duration. Avian perching techniques were observed to build a hypothesis for the biological control techniques employed during the landing maneuver. Variation of Wing Sweep for pitch control was identified as a contributing control method, and selected for study. A biologically-inspired aircraft was designed with variable Wing Sweep, and modeled using a combination of MATLAB and Athena Vortex Lattice (AVL) to predict pitching response due to Wing Sweep. A small remote controlled prototype was built with variable Wing Sweep in addition to standard flight control surfaces. An onboard microcontroller and inertia measurement unit (IMU) were used to record pitch and Wing Sweep data during flight. Pitch response to Wing Sweep was observed, and a proportional integral derivative (PID) control system was designed to successfully use Wing Sweep for closed loop pitch control
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Investigating the use of Wing Sweep for pitch control of a small unmanned air vehicle - eScholarship
2011Co-Authors: Kim WrightAbstract:Small Unmanned Air Vehicles (UAVs) are versatile tools with both civilian and military applications. Fixed Wing UAVs require forward airspeed to remain airborne, usually resulting in constant energy expenditure to loiter over targets. A UAV capable of perching could reduce energy expenditure by settling on a site near the target, thus increasing mission duration. Avian perching techniques were observed to build a hypothesis for the biological control techniques employed during the landing maneuver. Variation of Wing Sweep for pitch control was identified as a contributing control method, and selected for study. A biologically-inspired aircraft was designed with variable Wing Sweep, and modeled using a combination of MATLAB and Athena Vortex Lattice (AVL) to predict pitching response due to Wing Sweep. A small remote controlled prototype was built with variable Wing Sweep in addition to standard flight control surfaces. An onboard microcontroller and inertia measurement unit (IMU) were used to record pitch and Wing Sweep data during flight. Pitch response to Wing Sweep was observed, and a proportional integral derivative (PID) control system was designed to successfully use Wing Sweep for closed loop pitch control
A. Mazidi - One of the best experts on this subject based on the ideXlab platform.
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Aeroelastic analysis of swept pre-twisted Wings
Journal of Fluids and Structures, 2020Co-Authors: S. Ahmad Fazelzadeh, M. Rezaei, A. MazidiAbstract:Abstract In this paper, aeroelastic modeling of aircraft Wings with variations in Sweep angle, taper ratio, and variable pre-twist angle along the span is considered. The Wing structure is modeled as a classical beam with torsion and bending flexibility. The governing equations are derived based on Hamilton’s principle. Moreover, Peters’ finite state aerodynamic model which is modified to take into account the effects of the Wing finite-span, the Wing Sweep angle, and the Wing pre-twist angle, is used to simulate the aerodynamic loads on the Wing. The coupled partially differential equations are discretized to a set of ordinary differential equations using Galerkin’s approach. By solving these equations the aeroelastic instability conditions are derived. The results are compared with some experimental and analytical results of previous published papers and good agreement is attained. Effects of the Wing Sweep angle, taper ratio, bending to torsional rigidity, and pre-twist angle on the flutter boundary in several cases are studied. Results show that these geometrical and physical parameters have considerable effects on the Wing flutter boundary.
Ning Qin - One of the best experts on this subject based on the ideXlab platform.
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Drag Reduction for Transonic Wings Combining Reduced Wing Sweep with Shock Control
28th International Symposium on Shock Waves, 2012Co-Authors: Ning QinAbstract:In this paper, the potential of unlocking Wing Sweep on aircraft drag reduction is explored in the context of recent development in shock control by three dimensional bumps on natural laminar flow(NLF) Wings. Reduction of the Wing Sweep currently employed for large transport transonic aircraft is advocated for significant drag reduction, enabling natural laminar flow Wing development with shock control. The aim is to unlock a normally fixed design variable (for large transonic aircraft), i.e. Wing Sweep, in order to achieve substantial drag reduction through extended natural laminar flow area while keeping the shock strength and its impact on wave drag under control. A decrease of the current transonic Wing Sweep angle is anticipated to accommodate the natural laminar flow target, because of the potential alleviation of attachment line transition and crossflow boundary layer instability. The paper demonstrates the effects of 3D shock control bumps from zero to 20Sweep and from 2D sectional to 3D NLF Wings for cruise Mach number from 0.68 to 0.85.
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Study of the effects of Wing Sweep on the aerodynamic performance of a blended Wing body aircraft
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2007Co-Authors: Spiridon Siouris, Ning QinAbstract:AbstractThis article presents a study of the effects of Wing Sweep on the aerodynamic performance of a blended Wing body (BWB) aircraft that is based on an aerodynamically optimized design with a fixed planform and pitching moment constraint. Sixteen BWB geometries with varying Wing Sweep angles ranging from −40° (forward Sweep) to 55° Sweep were evaluated, while keeping the aerofoil profiles and twist distribution unchanged from the original optimized geometry. This gives some insight into the effects of one of the key planform design parameters.Numerical simulations were carried out using Euler solutions of the flow field with adaptive unstructured grids. Grid sensitivity studies were carried out, along with grid adaptation, on all geometries for solution accuracy. Results show that within 10° −55° Sweep, there is significant variation in the lift-to-drag ratio (LID), whereas for Sweep values from −40° to 10°, the L/D ratio remained relatively constant. To maintain the design lift for varying Wing Sweep...
P. Geuzaine - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Variable Wing-Sweep for Applications in Micro Air Vehicles
Infotech@Aerospace, 2005Co-Authors: Kamran Mohseni, Dale Lawrence, P. GeuzaineAbstract:Micro Air Vehicles (MAVs) are noted for their small size and low-Reynolds number flight regime. Because they have small mass, they are attractive for use in sensing of toxic plumes. This mission requires high aerodynamic efficiency and the ability to be quickly and easily launched. A variable-Sweep Wing is investigated to meet these goals. Numerical simulations are used to demonstrate that Sweeping the Wings can provide plausible drag characteristics over a range of flight speeds. By Sweeping the Wing from 15◦ to 65◦, L/D is improved by a factor of 2.6 at high speeds. This is caused by a decrease in parasitic drag corresponding to increased Sweep angle.
