Solid State Phenomena Vol. 198

Abstract: Turbine engines need to produce the thrust from several to about one thousand kilograms of the air per second depending on the engine type. Due to the demand for such a significant amount of the air a unique three dimensional field of speed occurs in the area of the intake vicinity. The characteristic feature of this field, when the engine runs on the ground, is generation of an inlet stagnation line and a stagnation point. In case of the aircraft engines, a vortex is developed chiefly due to external disturbances e.g. because of crosswind gusts or a stream of engine exhaust from another aircraft. This may lead to serious damage of fan or compressor blades and, additionally, affect the stability of engine operation. This paper addresses selected issues related to development of a model for a turbine engine intake, describes the course of modeling procedures for both the engine intake and its vicinity and selection of boundary conditions as well as the solution algorithm that involves the numerical analysis of the intake vortex formation. The purpose of the analyses performed was to define how variations of the engine speed, the angle and direction of wind gusts affect formation of the intake vortex.

Abstract: Designing and building of the unmanned aircraft, especially light and ultra light vehicles, is mainly performed using the experience gained when constructing the flying models. There have not been uniform principles of building and exploiting of the mini and micro UAV (Unmanned Aerial Vehicle) in the form of regulations similar to those for manned airplanes. The unmanned vehicles of these classes in terms of their abilities and attractive price are more frequently exploited using the same air area as manned airplanes performing missions over the inhabited areas. An urgent necessity arises to work out the norms of flight suitability of the mini and micro unmanned aerial vehicles. The work contains the analysis of suitability of the current aviation regulations to determine the requirements for the mini unmanned vehicles. The work concentrates on the phenomenon of determining the symmetrical loads from the maneuvers and the turbulence atmosphere. The result of this analysis is the Limit Maneuver Envelope, Limit Gust Envelope and Limit Combined Envelope for mini UAV. The analyzed flight states allowed selecting the so called design cases which can become a basis for determining the norms of loading of mini unmanned aerial vehicles which can constitute the beginning of the regulations for building of the unmanned aerial vehicles of this class.

Abstract: As part of the RTRA funded EMMAV (Electroactive Morphing for Micro-Airvehicles) research program electroactive materials were studied as well as their applications as actuators for morphing wings. The aim of this research program is to study both the actuation with large displacements at low frequencies as well as low displacement, high frequency actuation. The large displacement actuation, which targets primarily the flight control, is achievable using Shape Memory Alloys (SMA) while high frequency; low displacement actuation can be achieved using piezoelectric actuators [. This high frequency actuation is especially interesting for improving the aeroelastic coupling effect inducing both noise and drag. This paper describes the construction of a prototype incorporating piezoelectric and SMA based actuation mechanisms. Furthermore, a cooling mechanism for SMAs is described aiming at improving the cycle time of the actuator. The developed prototype is to be evaluated during wind-tunnel experiments showing the influence of the actuation on the fluid.

Abstract: This paper presents modeling, simulation, and control of a flapping wing Micromechanical Flying Insect (MFI) called Entomopter. The overall geometry of this MFI is based on hummingbirds and large insects. This paper presents methods for investigation of MFI aerodynamics, flight dynamics, and control. The simulation results reveal important information regarding the behavior of the system, that could be used in future designs

Abstract: The paper describes matters of modeling and control of aerial vehicle in rotorcraft configuration. Equations of motion were derived and dynamic model of six-rotor was build. To find the best adjustment of model to real object the dynamics of the drives was joined to the control plant model. Trimming and linearization were performed. Open loop system and LQR controller were checked in simulation environment. Next the faults of the actuator/sensor elements were arranged and the minimal number of observed outputs and drives for LQR stabilization process were specified.

Abstract: This paper describes comparison between virtual simulation of quadrotor flying platforms (mini UAV - Unmanned Aerial Vehicle) and real experiments. In quadrotor helicopter (quadrocopter) air flows that are going out from rotors and affecting each other were simulated. Analysis of several helicopters that have different distances between rotors on different angular velocities were compared. During virtual simulation (with CFD Computational Fluid Dynamics software) there were conducted similar to real experiments with the use of scanned rotors (with 3D scanner) and same environment conditions. These experiments were compared with real experiments. Optimal gap distance between rotors is determined, when helicopter mass is minimum and rotors are creating maximum lifting force and consuming minimum energy (minimum impact on air flows to each other).

Abstract: The paper presents integration process of commercial autopilot. The autopilot was integrated with a fixed wing airframe. The main aim of this work was an experimental study of the autopilot integrated with a micro aircraft. A few manual and autonomous mode flights were performed. During the field trials the autopilot PID parameters were tuned and, as a result, the process of PID gains selection was described. Selected PID gains were presented. Certain telemetry parameters such as longitudinal and lateral position of aircraft, orientation angles, and angular velocities were logged during flight and analyzed. Maximum and minimum airspeeds at a desired altitude were measured and presented. Moreover, Received Signal Strange Indicator between ground station and UAV equipped with special antenna was measured and logged for radio communication quality and range checking. Presented analysis of the autopilots work and obtained results were used to assess the applicability of this hardware to next formation flight operations.

Abstract: Avionics system software development is a sophisticated process depended on not fully specified factors. Therefore, essential steps in the development process are tests and verification. In this aim the virtual environment was constructed and prepared for the tests with the target software and the hardware to eliminate hardware defects and software bugs before first flight. The concept of virtual environment was established and developed after unsuccessful flights with long term prepared aircraft models. There was assumed that modelling methods applied separately to frame, engine and control system were not sufficient. There was requirement for complex simulation platform prepared to test whole aircraft in various environment conditions. In the first step the designing process was identified and milestones were placed inside (Fig. 1)

Abstract: In this paper some numerical simulations of the Navier-Stokes Equations (NSE) to test the novel NS-α and NS-ω turbulence models [1, , which conserve energy, enstrophy, and helicity, are presented. These algorithms verify more conservation properties than other implementations of the NSE, however their rotational form [ makes the scaling study of the coupling between the velocity and pressure errors with respect to the Reynolds number, a very interesting research line. Nowadays we are designing a wing profile in the context of Unmanned Aerial Vehicle (UAV) on incompressible flow conditions [. First a genetic algorithm (GA) is used to obtain the optimized design geometry and then the NS-α and NS-ω turbulence models are run to study its performance for different attack angles. The GA objective function evaluates the general potential theory of each wing section considered, because that requires less computational cost than the alternative of solving the NSE, and a wing design method proposed in [ is applied. Thus the optimized design geometry was found by evaluating the potential flow of all candidate solutions generated from the selection, crossover and mutation operators in each GA iteration. It takes the order of hundreds of simulations per iteration to evaluate all candidate solutions. Summarizing, two practical applications for a UAV are presented: the optimized design of an airfoil for environmental purposes, named CEANI airfoil, and the application of relevant turbulence models as NS-α and NS-ω in order to evaluate with accuracy the lift, drag and maximum angle of attack.

Abstract: In the conditions of the growing intensity of the UAV usage one of the most important problems is the improvement of their technical and performance effectiveness. It can be achieved applying the advanced methods of optimal designing. Apart from constructing an appropriate calculation model of the UAV, such an approach requires separating a group of decisive parameters, determining the limits and choosing the criterion of optimization. The precision and the range of use of the constructed calculation model must be adequate to a particular task allowing the optimal choice of characteristics of an aerial vehicle. Selection of the design parameters requires answering the question which technical parameters (geometrical, constructional etc.) of the UAV influence the performance characteristics of the aircraft positively. Analyzing the gradients of the performance characteristics change depending on the change in the design parameters, it is possible to determine the level of precision when determining the values and formulating the condition of finishing the optimization calculations. The aim of this work was to analyze the influence of selected design parameters on the performance characteristics of a mini UAV.