An assessment of the longitudinal motion of a hybrid configuration called the aerodynamically alleviated marine vehicle (AAMV) with the presence of waves, is demonstrated in the thesis. The development of this type of vehicle requires a mathematical framework to characterise its dynamics with the influence of external forces due to the waves’ motion. An overview of the effect of waves towards the models of dynamics developed for wing in ground effect (WIGE) craft and high-speed marine vehicles (planing craft) is carried out. However, the overview only leads to a finding that the longitudinal stability of a lifting surface over wavy ground effect is not entirely established. Taking this fact into account, the analysis of the model is proposed for a WIGE craft configuration. A simplification is adopted considering heave motion only in the modelling of oscillation. The simplification is made to thoroughly capture the effect of oscillation toward dynamic stability of the vehicle. To support the model verification, a numerical simulation followed by a semi-empirical design method was adopted to produce aerodynamic data, both in two-dimensional and three-dimensional domains, respectively. The results show that the combination of underpinning parameters, i.e. ride height, frequency and amplitude of oscillation, remarkably influence the aerodynamics. The characteristics in aerodynamics affect the production of stability derivatives and eventually stability behaviour of the chosen configuration. Some patterns in the results are identified but there also some data that show the peculiarity. Thus further investigation is needed.

The subject of this experimental investigation is to measure the dynamic stability derivatives in roll plane for an oscillating combat aircraft model by using forced oscillation technique. In forced oscillation technique the model is forced to oscillate around the center of gravity according to a harmonic motion of small amplitude and low frequency. The aerodynamic reactions are measured by an internal balance placed inside the model. The thesis presents a brief description of the test rig and the measurement system. The theory of dynamic stability derivatives and forced oscillation technique are also explained. The data is collected and analyzed by using a data acquisition system written with under the Labview programming language. Systematic analysis of the static and dynamic tests results and effect of various parameters (angle of attack, sideslip angle, oscillation frequency and amplitude, wind velocity) on these results are presented. Comparison of the present results with previous results obtained in other test facilities is also given. Design and manufacture process of a new angle of attack mechanism is also given in this thesis.

As the necessity of sustainable mobility rises, the demand to reduce the environmental impact of transporting mediums increases. The SUGAR Truss-Braced Wing (TBW) aircraft is a venture of Boeing, NASA and Virginia Tech for the N+3 generation of aircraft. These high-aspect-ratio aircraft are being designed with the aim to improve the structural and aerodynamic performance by implementing advanced technologies. Aerodynamics is a major factor influencing the performance of the aircraft, affecting the fuel consumption and emissions, especially due to drag. The multidisciplinary design optimization architecture for truss-braced-wing aircraft is dedicated to generate configurations with low fuel burn, maximum weight carrying capabilities and aircraft stability for long and medium range missions. The incorporation of flight dynamics at the conceptual design stage offers enhanced aerodynamic performance and wing flexibility for the aircraft. A robust flight dynamic system would need a detailed aerodynamic analysis of the aircraft with the focus on aeroelasticity. In this thesis, various aerodynamic coefficients and stability derivatives are investigated by applying Vortex-Lattice Method using OpenVSP, an open-source platform. The variation in aerodynamic parameters with changes in configurations and flow conditions are discussed as well. OpenVSP allows for study of these results with low computational expense. This will aid in efficient aerodynamic design and lay basis for flight dynamics analysis and its inclusion in the Multidisciplinary Design Analysis and Optimization (MDAO) framework. / Master of Science / The demand for sustainable mobility and green transportation is increasing. Reduction in the environmental impact of these mediums is the prime motivation for various research studies conducted in this domain. The SUGAR Truss-Braced Wing (TBW) aircraft configuration research, led by Boeing, NASA and Virginia Tech over the last two decades, aims at developing highly fuel-efficient next-generation aircraft. These high-aspect-ratio aircraft are being researched for improving the structural and aerodynamic performance by implementing advanced technologies. Aerodynamic performance of the aircraft influences the fuel consumption and emissions produced drastically. The current design optimization framework for the TBW aircraft focuses on development of these aircraft configurations with the goal to limit fuel burn and maximize payload carrying capability. Flight dynamics analysis can be significant to improve and obtain optimal solutions from the design process. Incorporation of flight dynamics at the conceptual design stage offers enhanced aerodynamic performance and wing flexibility for the next generation aircraft. Therefore, a detailed aerodynamic analysis of the aircraft would be needed to establish a systematic flight dynamics module. This thesis presents a new approach for formulating and analysing the aerodynamic coefficients and stability derivatives by implementing Vortex-Lattice Method available in the open-source software. This will further allow for inclusion of flight dynamics study of the new configurations for long and medium range missions within the existing framework.

A mathematical model for the determination of the aerodynamic forces acting on an aircraft is presented. The mathematical model is based on the generalization of the idea of aerodynamically steady motions. One important use of these results is the determination of steady (time-invariant) aerodynamic forces and moments. Such aerodynamic forces can be determined using computer simulation by determining numerically the associated steady flows around the aircraft when it is moving along such generalized steady trajectories. The method required the extension of standard (inertial) CFD formulations to general non-inertial reference frames. Generalized Navier-Stokes and Euler equations have been derived. The formulation is valid for all ranges of Mach numbers including transonic flow. The method was implemented numerically for the planar case using the generalized Euler equations. The developed computer codes can be used to obtain numerical flow solutions for airfoils moving in general steady motions (i.e. circular motions). From these numerical solutions it is possible to determine the variation of the lift, drag and pitching moment with respect to the pitch rate at different Mach numbers and angles of attack. One of the advantages of the mathematical model developed here is that the aerodynamic forces become well-defined functions of the motion variables (including angular rates). In particular, the stability derivatives are associated with partial derivatives of these functions. These stability derivatives can be computed using finite differences or the sensitivity equation method. / Ph. D.

The objective of the present research is to investigate unsteady aerodynamic models with state equation representations that are valid up to the high angle of attack regime with the purpose of evaluating them as computationally affordable models that can be used in conjunction with the equations of motion to simulate wing rock. The unsteady aerodynamic models with state equation representations investigated are functional approaches to modeling aerodynamic phenomena, not directly derived from the physical principles of the problem. They are thought to have advantages with respect to the physical modeling methods mainly because of the lower computational cost involved in the calculations. The unsteady aerodynamic multi-axis models with state equation representations investigated in this report assume the decomposition of the airplane into lifting surfaces or panels that have their particular aerodynamic force coefficients modeled as dynamic state-space models. These coefficients are summed up to find the total aircraft force coefficients. The products of the panel force coefficients and their moment arms with reference to a given axis are summed up to find the global aircraft moment coefficients. Two proposed variations of the state space representation of the basic unsteady aerodynamic model are identified using experimental aerodynamic data available in the open literature for slender delta wings, and tested in order to investigate their ability to represent the wing rock phenomenon. The identifications for the second proposed formulation are found to match the experimental data well. The simulations revealed that even though it was constructed with scarce data, the model presented the expected qualitative behavior and that the concept is able to simulate wing rock. / Ph. D.