Aerodynamic Modeling of a Flapping Membrane Wing Using Motion Tracking Experiments

Aerodynamic Modeling of a Flapping Membrane Wing Using Motion Tracking Experiments

Abstract :-
An analytical model of flapping membrane wing aerodynamics using experimental kinematic data is presented. An alternative to computational fluid dynamics, this experimental method tracks small reflective markers placed on two ornithopter membrane wings. Time varying three dimensional data of the wing kinematics and the corresponding aerodynamic loads were recorded for various flapping frequencies. Continue reading Aerodynamic Modeling of a Flapping Membrane Wing Using Motion Tracking Experiments

Aerodynamic Analysis of an MAV-Scale Cycloidal Rotor System Using a Stuctured Overset RANS Solver

Aerodynamic Analysis of an MAV-Scale Cycloidal Rotor System Using a Stuctured Overset RANS Solver

Abstract :-
A compressible Reynolds-Averaged Navier-Stokes solver was used to investigate the performance and flow physics of the cycloidal rotor (cyclocopter). This work employed a computational methodology to understand the complex aerodynamics of the cyclocopter and its relatively unexplored application for MAVs. The numerical code was compared against performance measurements obtained from experiment and was seen to exhibit reasonable accuracy. With validation of the flow solver, CFD predictions were used to gain qualitative insight into the flowfield. Time histories revealed large periodic variations in thrust and power. In particular, the virtual camber effect was found to significantly influence the vertical force time history. Spanwise thrust and flow visualizations showed a highly three-dimensional flowfield with large amounts of blade shedding and blade-vortex interaction. Overall, the current work seeks to provide unprecedented insight into the cyclocopter flowfield with the goal of developing an accurate predictive tool to refine the design of future cyclocopter configurations.

Author:- Yang, Kan

Source:- DRUM

Aerodynamic Analysis and Simulation of a Twin-Tail Tilt-Duct Unmanned Aerial Vehicle

Aerodynamic Analysis and Simulation of a Twin-Tail Tilt-Duct Unmanned Aerial Vehicle

Abstract :-
The tilt-duct vertical takeoff and landing (VTOL) concept has been around since the early 1960s; however, to date the design has never passed the research and development phase. Nearly 50 years later, American Dynamics Flight Systems (ADFS) is developing the AD-150, a 2,250lb weight class unmanned aerial vehicle (UAV) configured with rotating ducts on each wingtip. Unlike its predecessor, the Doak VZ-4, the AD-150 features a V tail and wing sweep- both of which affect the aerodynamic behavior of the aircraft. Because no aircraft of this type has been built and tested, vital aerodynamic research was conducted on the bare airframe behavior (without wingtip ducts). Continue reading Aerodynamic Analysis and Simulation of a Twin-Tail Tilt-Duct Unmanned Aerial Vehicle

Adaptive Magnetorheological Sliding Seat System for Ground Vehicles

Adaptive Magnetorheological Sliding Seat System for Ground Vehicles

Abstract :-
Magnetorheological (MR) fluids (MRFs) are smart fluids that have reversible field dependent rheological properties that can change rapidly (typically 5 – 10 ms time constant). Such an MRF can be changed from a free flowing fluid into a semi-solid when exposed to a magnetic field. The rapid, reversible, and continuous field dependent variation in rheological properties can be exploited in an MRF-based damper or energy absorber to provide adaptive vibration and shock mitigation capabilities to varying payloads, vibration spectra, and shock pulses, as well as other environmental factors. Continue reading Adaptive Magnetorheological Sliding Seat System for Ground Vehicles

Active Suppression of Vortex-Driven Combustion Instability Using Controlled Liquid-Fuel Injection

Active Suppression of Vortex-Driven Combustion Instability Using Controlled Liquid-Fuel Injection

Abstract :-
Combustion instabilities remain one of the most challenging problems encountered in developing propulsion and power systems. Large amplitude pressure oscillations, driven by unsteady heat release, can produce numerous detrimental effects. Most previous active control studies utilized gaseous fuels to suppress combustion instabilities. However, using liquid fuel to suppress combustion instabilities is more realistic for propulsion applications. Continue reading Active Suppression of Vortex-Driven Combustion Instability Using Controlled Liquid-Fuel Injection

Abort Trajectories for Manned Lunar Missions

Abort Trajectories for Manned Lunar Missions

Abstract :-
With NASA’s renewed focus towards a permanent human presence on the moon, comes the development of the Crew Exploration Vehicle. Unforeseen circumstances can induce emergency situations necessitating contingency plans to ensure crew safety. It is therefore desirable to define the feasibility of a direct abort from an outbound translunar trajectory. Continue reading Abort Trajectories for Manned Lunar Missions