Rotors are a crucial component of VTOL(vertical take-off and landing) devices like unmanned aerial vehicles (UAVs) or helicopters, etc., By generating a rotational force, they create the necessary thrust to lift and maneuver the vehicle in the air. In recent years, there has been a growing emphasis on developing rotor designs that are more efficient and effective for eVTOL. This has led to the emergence of several unconventional swept rotor designs that can improve aerodynamic and aeroacoustic performance. The present thesis aims to investigate the impact of achieving a balanced sweep distribution across a rotor blade and how it affects aerodynamic performance. The study explores the potential benefits and drawbacks of unconventional swept rotor designs and compares their performance curves to traditional straight rotor designs. The investigation begins with an overview of rotor design criteria and literature on swept rotor designs. A comprehensive design and analysis of the aerodynamic performance of various rotor designs are conducted using NASA's OpenVSP and VSPAero, a low-fidelity solver that implements the Vortex lattice method. The results are then compared with wind tunnel experiments. Based on the load distribution analysis of multiple sweep designs, it is noted that swept rotors exhibit decreased performance at lower advance ratios. However, as the speed or advance ratio increases, the overall performance of swept rotors significantly improves. This conclusion is drawn from the load distribution data obtained for each blade of the rotors, and by comparing the figure of merit (FOM) of various designs. / Master of Science / Picture this: a sleek unmanned aerial vehicle (UAV) soaring through the air, its Propellers whirring efficiently and quietly. What makes this possible? The answer lies in the design of the rotors themselves. Rotors are critical components of UAVs, providing the necessary thrust to lift and maneuver the vehicle in the air. And with the growing demand for more efficient and effective eVTOLs (Vertical take-off and Landing) vehicles, unconventional swept rotor designs have emerged as game-changers in the industry. The present thesis delves into the impact and effects of Parametric swept designs on rotor aerodynamic performance. The study seeks to uncover the potential benefits and drawbacks of these designs and compare their performance curves to traditional straight rotor designs. The study starts by looking at how rotors are designed and what others have done with similar designs. Various rotor designs have been thoroughly examined in terms of their aerodynamic characteristics using NASA's OpenVSP and VSPaero, a low-fidelity solver that uses the Vortex lattice method. To verify the tools, this data are compared with wind tunnel tests. Due to its cheap computing cost, OpenVSP makes it possible to investigate these discoveries in an economical manner. According to the results, swept rotors perform better at higher speeds than conventional rotors.

<p>The workin this thesis deals with the development of anaeroelastic simulation tool for horizontal axis wind turbineapplications.</p><p>Horizontal axiswind turbines can experience significanttime varying aerodynamic loads, potentially causing adverseeffects on structures, mechanical components, and powerproduction. The need of computational and experimentalprocedures for investigating aeroelastic stability and dynamicresponse have increased as wind turbines become lighter andmore flexible.</p><p>A finite element model for simulation of the dynamicresponse of horizontal axis wind turbines has been developed.The simulations are performed using the commercial finiteelement software SOLVIA, which is a program developed forgeneral analyses, linear as well as non-linear, static as wellas dynamic. The aerodynamic model, used to transform the windflow field to loads on the blades, is a Blade- Element/Momentummodel. The aerodynamic code is developed by FFA (TheAeronautical Research Institute of Sweden) and is astate-of-the-art code incorporating a number of extensions tothe Blade-Element/Momentum formulation. SOSIS-W, developed byTeknikgruppen AB was used to develop wind time series formodelling different wind conditions.</p><p>The model is rather general, and different configurations ofthe structural model and various type of wind conditions couldeasily be simulated. The model is primarily intended for use asa research tool when influences of specific dynamic effects areinvestigated.</p><p>Simulation results for the three-bladed wind turbine Danwin180 kW are presented as a verification example.</p><p><b>Keywords:</b>aeroelastic modelling, rotor aerodynamics,structural dynamics, wind turbine, AERFORCE, SOSIS-W,SOLVIA</p>

Helicopter flight dynamic, rotor aerodynamic and dynamic analyses activities have been a great dispute since the first helicopters, at both design and test stages. Predicting rotor aerodynamic and dynamic characteristics, helicopter dynamic behavior and trimmed flight conditions is a huge challenge to engineers as it involves the tradeoff between accuracy, fidelity, complexity and computational cost. Flight dynamic activities such as / predicting trim conditions, helicopter dynamic behavior and simulation of a flight condition or maneuver mostly require analysis tools with low computational cost and complexity. However this decreases accuracy and fidelity of the model. On the other hand, analyses at design stages, such as / blade geometric and structural design mostly requires accurate and higher fidelity aerodynamic load predictions over the rotor disk. Contrarily this brings high computational cost and complexity. Therefore separate analysis tools for each objective or one complete tool that can be used for all purposes are essential. Throughout this study a helicopter mathematical including trim model with a selective and modular structure is developed as a generic analysis tool. The selective structure enables the mathematical model to be used in both flight dynamic and comprehensive analysis while the modular structure plays a role as an infrastructure for further developments. The mathematical model developed is validated with flight test data of several helicopters. Besides, commercial helicopter comprehensive analysis tools are used to validate the mathematical model analyses. Results showed good agreement with the compared data.

The workin this thesis deals with the development of anaeroelastic simulation tool for horizontal axis wind turbineapplications. Horizontal axiswind turbines can experience significanttime varying aerodynamic loads, potentially causing adverseeffects on structures, mechanical components, and powerproduction. The need of computational and experimentalprocedures for investigating aeroelastic stability and dynamicresponse have increased as wind turbines become lighter andmore flexible. A finite element model for simulation of the dynamicresponse of horizontal axis wind turbines has been developed.The simulations are performed using the commercial finiteelement software SOLVIA, which is a program developed forgeneral analyses, linear as well as non-linear, static as wellas dynamic. The aerodynamic model, used to transform the windflow field to loads on the blades, is a Blade- Element/Momentummodel. The aerodynamic code is developed by FFA (TheAeronautical Research Institute of Sweden) and is astate-of-the-art code incorporating a number of extensions tothe Blade-Element/Momentum formulation. SOSIS-W, developed byTeknikgruppen AB was used to develop wind time series formodelling different wind conditions. The model is rather general, and different configurations ofthe structural model and various type of wind conditions couldeasily be simulated. The model is primarily intended for use asa research tool when influences of specific dynamic effects areinvestigated. Simulation results for the three-bladed wind turbine Danwin180 kW are presented as a verification example. <b>Keywords:</b>aeroelastic modelling, rotor aerodynamics,structural dynamics, wind turbine, AERFORCE, SOSIS-W,SOLVIA / NR 20140805

The work in this thesis deals with the development of an aeroelastic simulation tool for horizontal axis wind turbine applications. Horizontal axis wind turbines can experience significant time varying aerodynamic loads, potentially causing adverse effects on structures, mechanical components, and power production. The needs for computational and experimental procedures for investigating aeroelastic stability and dynamic response have increased as wind turbines become lighter and more flexible. A finite element model for simulation of the dynamic response of horizontal axis wind turbines has been developed. The developed model uses the commercial finite element system MSC.Marc, focused on nonlinear design and analysis, to predict the structural response. The aerodynamic model, used to transform the wind flow field to loads on the blades, is a Blade-Element/Momentum model. The aerodynamic code is developed by The Swedish Defence Research Agency (FOI, previously named FFA) and is a state-of-the-art code incorporating a number of extensions to the Blade-Element/Momentum formulation. The software SOSIS-W, developed by Teknikgruppen AB was used to generate wind time series for modelling different wind conditions. The method is general, and different configurations of the structural model and various type of wind conditions can be simulated. The model is primarily intended for use as a research tool when influences of specific dynamic effects are investigated. Verification results are presented and discussed for an extensively tested Danwin 180 kW stall-controlled wind turbine. Code predictions of mechanical loads, fatigue and spectral properties, obtained at different conditions, have been compared with measurements. A comparison is also made between measured and calculated loads for the Tjæreborg 2 MW wind turbine during emergency braking of the rotor. The simulated results correspond well to measured data. / QC 20100826