A5089623419- Aerodynamics and Acoustics in Jet Flows
- Vehicle Noise and Vibration Control
- Acoustic Wave Phenomena Research
- Computational Fluid Dynamics and Aerodynamics
- Aerodynamics and Fluid Dynamics Research
- Fluid Dynamics and Turbulent Flows
- Noise Effects and Management
- Engineering Applied Research
- Aeroelasticity and Vibration Control
- Aerospace and Aviation Technology
- Wind and Air Flow Studies
- Combustion and Detonation Processes
- Gas Dynamics and Kinetic Theory
- Particle Dynamics in Fluid Flows
- Structural Engineering and Vibration Analysis
- Structural Load-Bearing Analysis
- Rocket and propulsion systems research
- Turbomachinery Performance and Optimization
- Scientific Research and Discoveries
Korea Aerospace University
2024
Georgia Institute of Technology
2023-2024
Seoul National University
2015-2022
A comprehensive multirotor noise assessment framework is developed to predict the of rotational-speed-controlled rotor configurations in real-time. The key objectives are synthesize frequency-modulated and analyze frequency modulation (FM) characteristics. includes modules associated with flight control, aerodynamics, time reconstruction, prediction, time-frequency analysis (TFA). In addition hybrid blade element momentum model, aerodynamics module contains a linear inflow Beddoes wake an...
This study presents a comprehensive numerical framework for auralizing multirotor noise during complex maneuvers, incorporating rotor tonal and broadband prediction, synthesis, psychoacoustic analysis. Validation studies various flight scenarios, including single rotors quadrotors, confirm the capability of this in prediction-based analysis configurations. The primary focus research is to assess flyover takeoff multirotors under diverse operating conditions. When tracking mission profile...
A stochastic numerical analysis of a multirotor was performed considering the rotational speed fluctuation to investigate acoustic characteristics. To validate analysis, noise measured in an anechoic chamber at different azimuth angles (from 0° 45°) and polar 67.5°) revolutions per minute (RPM) assuming hovering maneuver. Frequency amplitude modulation characteristics due RPM fluctuations were observed despite considered condition. Moreover, azimuthal directivity pattern circular shape...
In this Paper, the wake dynamics of coaxial rotors are studied using high-wake-resolution method. The method is a novel combination truncated vortex tube model for initial and boundary conditions wave-number-extended finite-volume interpolation scheme. resolution verified by comparison with other general computational fluid techniques. By method, Paper analyses different inter-rotor spacing. aerodynamic characteristics compared those single-rotor systems to identify effect interaction on...
A preliminary investigation of the noise abatement landing approach for multirotor urban air mobility (UAM) vehicle is carried out using comprehensive assessment (CONA) framework. The key objectives are to identify low-noise condition UAM vehicles reduce ground impact near zone. CONA framework, developed by our research team, has capability trajectory-based prediction RPM-controlled configurations. It uses parameterized Beddoes wake model with regression analysis consider aerodynamic...
This study aims to analyze the impact of wind on community noise generated by urban air mobility (UAM) vehicle landing operations. Given influence atmospheric environments UAM vehicles during landing, incorporating profiles into numerical frameworks is crucial for accurate assessment. The focus numerically examining variations in acoustic sources resulting from flight control mechanisms, specifically different trim conditions leading wake interactions under wind. Various are investigated,...
This study numerically investigates the community noise impact of multirotor aerial vehicles during landing procedures. Under various operating conditions, physical and psychological impacts operations are evaluated by source hemispheres maps using auralization process for noise. Performance contours defined to compare constraints, such as energy consumption, duration, vehicle attitudes, safety concerns between two configurations with different rotor scales. The operational environments...
This research conducts a comparative analysis of the aerodynamic and aeroacoustic characteristics fixed-pitch variable-pitch controlled multirotors [i.e., revolution per minute (RPM) collective pitch control]. The study encompasses single-, twin-, quad-rotor configurations under hovering flight conditions. unsteady blade motion is modeled as function RPM pitch, fluctuating with frequency amplitude. To comprehensively account for wake interaction effects, free-wake vortex lattice method...
This research conducts a comparative analysis of the aerodynamic and aeroacoustic characteristics fixed-pitch variable-pitch controlled multirotors (i.e., revolution per minute collective pitch control). The study encompasses hovering forward flight conditions, considering wind gust effects. Specifically, high-resolution time-frequency is conducted to investigate interference modulation effects multirotor noise. reveals significant variations in spectral depending on control method. Notably,...
This study numerically investigates the noise impact of multirotor aerial vehicles with different rotor scales during landing procedures. The operational environments individual rotors are influenced by rotational speed and wake dynamics, leading to variations in characteristics. Noise impacts evaluated across various operations from both physical psychoacoustic perspectives using source hemispheres maps. is quantified sound exposure level (SEL), while assessed through a annoyance (PA) based...
본 논문에서는 구조물에 작용하는 하중의 크기와 진동수에 따른 거동의 비선형성을 확인하고 정확한 예측을 위한 방법을 모색하기 위하여 외팔보의 정적 및 동적해석의 수행에서 선형, 비선형 해석의 결과를 비교하는 연구를 진행하였다. 우선 보의 자유단에 수직방향의 동적 하중을 가한 상황을 예측하였다. 선형 해석방법으로 고전 외팔보 이론을 적용하였고, co-rotational dynamic 유한요소해석 기법을 개발하여 사용하였다. 먼저 정적해석에서 외력의 크기가 달라질 때 해석 예측이 어떠한 차이를 보이는지 비교하였다. 그리고 동적해석을 통해 가진 진동수의 변화에 보 끝단의 무차원화된 변위의 양상을 연구하였고, 공진진동수 근방에서의 상당한 변위가 발생함을 보였다. 마지막으로 주파수 지연현상을 조사하기 위해 특정 진동수에서의 시간 경과에 변위를 확인하였다.In this paper, the behaviour of a cantilevered beam was predicted to...
During a lift-off of launch vehicle, large amount acoustic wave is generated by jet plumes. Acoustic waves lead to pressure fluctuations on the surface vehicle in form loads and these are transmitted internal payload. In order evaluate effects loads, we developed integrated simulation model. The model mainly divided into two parts, prediction reduction parts. First, external predicted empirically based Distributing Source Method-II (DSM-II) NASA SP-8072. We improved method able consider...
수직이착륙기(VTOL) 및 도심 항공 모빌리티와 같은 멀티로터형 비행체는 높은 기동성을 바탕으로 오늘날 널리 활용되고 있다. 멀티로터는 다수의 로터로 구성되어 후류 상호작용이 활발히 발생하고, 이로 인해 멀티로터의 공기역학 공력음향학적 특성이 단일 로터와 큰 차이를 보인다. 본 연구에서는 자유 격자 기법 해석자를 활용하여 상호작용 효과를 규명하고자 하였다. 다양한 비행체와 운용조건의 비교를 위하여, 제자리 비행에서 로터 간격에 따른 효과와 전진 전진비 방향에 확인하였다. 비행 시 사이의 상호작용으로 비정상 하중이 발생하였으며, 사이 간격이 줄어들수록 하중 변화폭이 증가하였다. 이는 소음을 발생시키고 소음 지향성에 변화를 가져온다. 시, 따라서 특성에서 해석 결과와 비교하였을 때, 각각의 로터는 상대적 위치에 소음의 크기와 지향성이 다르다. 결론적으로 효과에 대한 분석은 멀티로터 형상과 공력 공력소음 해석에 필수적이다.
The auralization can be an effective asset in the design of unmanned aerial vehicles (UAV) and urban air mobility vehicles, serving as a valuable resource decision-making regarding mitigation noise-related issues. However, order to effective, must perceptually accurate. During process auralization, multirotor noise evaluation framework based on multidisciplinary principles was employed model periodical fluctuations rotational speed. subjective response test utilized evaluate synthesized...