Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 14 of 14 for “"Flight Speeds"”.
-
Structure of an Ensemble of Insectivorous Bats
… wing morphology, echolocation characteristics, flight behaviour, habitat use, and diet. Using acoustic arrays I compared activity patterns at different sites to determine temporal and spatial partitioning and generated flight paths to determine flight speeds. From captured bats I measured wing …
-
Analysis of flutter and flutter suppression via an energy method
… decreased structural weight, and higher flight speeds. Preliminary designs often exhibit a flutter instability within the desired operating envelope of the aircraft. Passive methods which have been used to solve the flutter problem include added structural stiffness, mass balancing, and …
-
Vibration control and gust alleviation of highly flexible blended-wing-body aircraft
… experience in high-altitude, long-endurance flights is critical to improving their flight performance and maintaining stable flight. Aircraft designed for high-altitude, long-endurance flights tend to be more flexible due to the design requirements of their missions. The aircraft may …
-
Development of an Experimental System to Generate and Characterize Supersonic Aerosol Particles Using Laser Doppler Velocimetry
There is current concern regarding high-speed flight vehicle encounters with aerosols and the surface damage resulting from particle impacts during flight. To investigate and characterize the damage potential of aerosol particles at flight speeds, a bench-top system was developed. This system is …
-
Supermaneuverable perching
… of stabilizing the maneuver over a wide range of flight speeds and quantify its robustness to wind-gust disturbances. In order to better characterize the aerodynamics during perching, we performed smoke-visualization in a low-speed free flight wind-tunnel, where we were able to capture real images …
-
Evaluation of hot surface ignition device performance with high-pressure kerosene fuel sprays
… vehicles (UAVs) designed to operate at moderate flight speeds. However, one of the primary limitations of CI engines is that they require well-characterized, highly-reactive diesel fuel to operate properly. As the United States Department of Defense implements the single fuel concept and with …
-
Effects of Duct Lip Shaping and Various Control Devices on the Hover and Forward Flight Performance of Ducted Fan UAVs
… leading edge radius performed best in forward flight and crosswind conditions, while the performance of a lip with a large leading edge radius was enhanced in static conditions. Through tuft flow visualization and static pressure measurements it was determined that the reason for the difference …
-
Evaluation of a Strut-Plasma Torch Combination as a Supersonic Igniter-Flameholder
As the flight speeds of aircraft are increased above Mach 5, efficient methods of propulsion are needed. Scramjets may be a solution to this problem. Supersonic combustion is one of the main challenges involved in the operation of a Scramjet engine. In general, both an igniter and a flameholder are …
-
Structural dynamics modeling of helicopter blades for computational aeroelasticity
… the steady state of a fixed wing at different flight speeds have been obtained and results are consistent with other methods. The time response of the active twist rotor (ATR) prototype blade in hover has also been examined. The twist response of ATR blade due to applied piezoelectric actuation …
-
Improved gust rejection for a micro coaxial helicopter in urban environments
… on the same order of magnitude as the maximum flight speeds of micro rotorcraft leading to stall, large attitude perturbations, and loss of control; thus preventing micro rotorcraft from carrying out even the most basic missions. This dissertation starts to fill the void in the literature on …
-
Sensing Atmospheric Winds from Quadrotor Motion
… with experimental methods to exploit the flight envelope of multirotor UAS for wind sensing. The parameters of three quadrotor motion models, consisting of a kinematic particle, a dynamic particle, and a dynamic rigid body models are developed to measure wind velocity in hovering flight. …
-
Unsteady Aerodynamics of Wing-Gust Encounters
… the performance of fixed wing aircraft. At low flight speeds, gusts transverse to the lifting surfaces can cause massive changes to the angle of incidence, fluctuations in lift and drag, and result in flight instability. This may be catastrophic for small drones, and hazardous for larger …
-
Aerodynamics and Power Balance of Boundary Layer Ingesting Aircraft
… design and operability of the aircraft. As the flight Mach number is reduced, the flow over the cowl is improved, but with the same FPR, this leads to increased loss in the exhaust region due to the higher ratio of jet to flight speeds, which has a strong effect on the mixing loss. At reduced …
-
Unsteady Aerodynamic and Aeroelastic Analysis of Flapping Flight
… aerodynamic and aeroelastic analysis of flapping flight under various kinematics and flow parameters is presented in this dissertation. The main motivation for this study arises from the challenges facing the development of micro air vehicles. Micro air vehicles by requirement are compact with …