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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Seidl, D. Thomas Geraci, Gianluca King, Ryan N. Menhorn, Friedrich Glaws, Andrew Eldred, Michael S. Sandia Natl Labs Optimizat & Uncertainty Quantificat Albuquerque NM 87123 USA Natl Renewable Lab Computat Sci Ctr Golden CO 80401 USA Tech Univ Munich Garching Germany Tech Univ Munich Dept Informat Garching Germany

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

The complexity of analyzing and designing wind power plants is significantly amplified when high-fidelity numerical simulations are integrated for evaluating performance. To accurately predict the performance of these systems, one requires both computational fluid dynamics simulations, to predict the flow evolution around each turbine and wake interactions among turbines, and structural simulations, to evaluate the mechanical loads. Moreover, wind power plants operate in an intrinsically stochastic environment and therefore the characterization of their performance also needs to include uncertainty quantification (UQ). UQ is the ensemble of tasks that deals with the characterization of the sources of uncertainty and their propagation through numerical codes. The characterization process is also known as inverse UQ, in that one must invert for the input distributions that are consistent with observed data, and the propagation task is also known as forward UQ, in that the characterized distributions are pushed forward through the numerical simulations to compute corresponding output distributions on quantities of interest. Both inverse and forward UQ algorithms, despite rapid advancements in recent years, still require a large number of numerical simulations to be performed to provide an acceptable accuracy in their solutions. In this work, we demonstrate how multifidelity surrogate-based strategies can be successfully coordinated and leveraged to reduce the overall computational burden of both inverse and forward UQ workflows applied to wind energy production.

关键词： Wind Energy computational fluid dynamics simulation Wind Power Plants Energy Production Structural simulation Reynolds Averaged Navier Stokes Wind Turbine Wakes Sandia National Laboratories Computing Turbulence Models

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Development of a Portable Electric Ducted Fan Engine Lab for Aircraft Electric Propulsion Education

Development of a Portable Electric Ducted Fan Engine Lab for...

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AIAA Propulsion and Energy Forum

作者： Salazar, David Liou, William W. Xu, Jin Western Michigan Univ Mech & Aerosp Engn Kalamazoo MI 49008 USA

ISBN: (数字)9781624106026

ISBN: (纸本)9781624106026

The paper describes the development of a new portable test capability for an electric ducted fan (EDF) engine to support sustainable aircraft propulsion education at Western Michigan University and the project outcomes. The objective of the first-of-its-kind EDF engine lab is to enrich classroom learning by bringing hands-on experience into classrooms and lecture hall. The EDF engine lab is purposely designed to operate with no external power source. Most hardware including the EDF engine, batteries, speed controller, microcontroller boards, and the sensors for data acquisition are commercially available. Variable inlet vanes are used for inlet mass flow control and a thrust-vector control is used for single-axis thrust vectoring. 3D printing is extensively used throughout the build to custom-make support structures and control surfaces. computational fluid dynamics simulations of the EDF engine have also been developed. The lab facility is constructed. Measured and simulated propulsion quantities, such as engine thrust, torque, and nozzle exit velocity are in good agreement. The portable EDF engine lab is successfully piloted by students in a senior level aerospace propulsion course.

关键词： Aircraft Propulsion Air Vehicle Thrust Vector Control Sensors computational fluid dynamics simulation Data Acquisition Electric Propulsion Control Surfaces Mass Flow Brushless Motor

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Validation of Simulated Urban Microscale Weather Pertinent to Aviation Interests

Validation of Simulated Urban Microscale Weather Pertinent t...

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AIAA Aviation Forum

作者： Robinson, Michael Klimenko, Victor Diao, Qina Bieringer, Paul Annunzio, Andrew MITRE Corp TFM En Route Concepts & Analysis Mclean VA 22102 USA Aeris Louisville CO 80027 USA

ISBN: (数字)9781624105982

ISBN: (纸本)9781624105982

An emergent aviation transportation evolution is underway which involves the rise of drone and electronic vertical take-off and landing (eVTOL) vehicle technology and the envisioned unmanned aircraft systems (UAS) and urban air mobility (UAM) applications, particularly in urban environments. One of many challenges however is determining when and where it is safe to operate in an urban environment, where complex microscale weather conditions created by channeled winds and turbulent eddies induced by buildings may transform otherwise benign conditions into hazards. A large-eddy simulation (LES) model considered highly capable for supporting urban UAS / UAM weather needs is the Joint Outdoor-indoor Urban Large Eddy simulation (JOULES) model, a graphics processing unit (GPU)-enabled computational fluid dynamics (CFD) model that can simulate horizontal and vertical winds and turbulence in urban domains down to 0.3 m (1 foot) resolution. MITRE and Aeris have begun examining how the JOULES model could be applied for mission-specific UAS and UAM weather hazard impact planning given a range of envisioned operations in urban environments. This paper presents the results from a novel methodology for comprehensive validation of LES-modeled estimates for microscale (2 m) horizontal and vertical wind conditions perturbed by buildings in a realistic urban environment. The validation directly compares the LES data with Magnetic Resonance Imager (MRI)-examined water tank fluid flow conditions within the same, scaled urban environment (Oklahoma City, OK: OKC). Validation results demonstrated that overall, across the different domains and specific flow comparison locations (including customized UAM climb and descent trajectories and UAS urban playbook flight paths), the JOULES model performed well in matching varied (and at times complex), time-averaged horizontal and vertical wind magnitude and direction. Validation results suggest that JOULES is well-suited to support urban microsca

关键词： Aviation Transportation computational fluid dynamics simulation Urban Air Mobility Unmanned Aircraft System Graphics Processing Unit Flow Conditions Magnetic Resonance Vertical Take off and Landing Vehicle Technology fluid Flow

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simulation and Modeling of Flow Generated by Gust Generator in a Wind Tunnel

Simulation and Modeling of Flow Generated by Gust Generator ...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Nguyen, Nhan Xiong, Juntao Cramer, Nicholas B. NASA Ames Res Ctr Intelligent Syst Div Moffett Field CA 94035 USA Stinger Ghaffarian Technol Inc Intelligent Syst Div Moffett Field CA 94035 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

A computational study of a gust field generated by a gust generator in a low-speed wind tunnel. The gust generator is designed for the University of Washington Aeronautical Laboratory (UWAL) Kirsten wind tunnel for a gust load alleviation (GLA) control experiment of a Common Research Model (CRM) flexible wing utilizing the Variable Camber Continuous Trailing Edge Flap (VCCTEF). The gust generator comprises four horizontal NACA 0015 gust generator vanes placed upstream of the test section. computational fluid dynamics simulations using a two-dimensional (2D) Unsteady-Reynolds-Averaged-Navier-Stokes (URANS) with k - omega Shear Stress Transport (SST) turbulence model provide detailed time-resolved information about the generated flow by the gust generator under prescribed sinusoidal motion. The characteristics of the induced flow by the gust generator are analyzed. A gust propagation model of the gust field is investigated. An unsteady lift model is developed using a varying-fidelity approach which includes a 2D interference aerodynamic model of the combined gust generator-wing system. The computed integrated unsteady lift is compared to experimental data for validation of the unsteady lift model. Both the amplitude and transport delay are found to be accurately captured by the unsteady lift model.

关键词： Low Speed Wind Tunnel Aerodynamic Interference Trailing Edge Flap Reynolds Averaged Navier Stokes computational fluid dynamics simulation Active Aeroelastic Wing Turbulence Models Critical Loading NACA Airfoil Airfoil Chord

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Application of a Diverging-Converging Duct to a FSAE Radiator System

Application of a Diverging-Converging Duct to a FSAE Radiato...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Thomas, Bryce Agarwal, Ramesh K. Washington Univ Dept Mech Engn & Mat Sci St Louis MO 63130 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

The focus of this paper is on the design process for the radiator ducting on the Washington University (Wash U) Formula Society of Automotive Engineers (SAE) racing team vehicle. The side-pods for the WUFR-19 vehicle are designed as a diverging-converging duct around the radiator in order to provide a sufficient mass flow rate through the heat exchanger to cool the engine, while minimizing drag on the vehicle. Internal computational fluid dynamics simulations are run in ANSYS Fluent on an individual channel of the radiator core. A parametric setup is used to iterate through multiple inlet conditions. The goal of these simulations is to determine the relationship between the ducting inlet size, ram pressure and mass flow rate through the radiator core, while also accounting for heat transfer from the radiator in airflow conditions. The usage of internal simulations with varying inlet conditions reduces simulation time when compared to external side-pod simulations that have higher computational requirements and would require geometry modification between simulations. Results show that reducing the inlet size increases the pressure drop across and mass flow rate through the radiator for inlet sizes above 80% of the cross-sectional area of the radiator. Smaller inlet sizes begin to restrict airflow causing the mass flow rate to decrease. An inlet size of 70% of the cross-sectional area of the radiator and an outlet size of 80% of the inlet size were implemented in order to fully cool the engine and minimize drag on the vehicle.

关键词： Radiator Model Thermal Boundary Condition Total Mass Flow Rate computational fluid dynamics simulation Heat Exchangers ANSYS Coolant Computer Aided Design Flow Conditions Temperature Sensors

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Further Investigation of Vertical Stabilizer with Passive Flow Control Devices

Further Investigation of Vertical Stabilizer with Passive Fl...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Ito, Yasushi Koike, Shunsuke Murayama, Mitsuhiro Ichikawa, Yoshiyasu Nakakita, Kazuyuki Yamamoto, Kazuomi Kusunose, Kazuhiro Japan Aerosp Explorat Agcy Aeronaut Technol Directorate Chofu Tokyo 1828522 Japan

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

This manuscript describes methods to improve the performance of a vertical stabilizer in terms of yawing moment with tip fence, leading-edge vortex generator and delta-shaped vortex generator passive flow control devices, in addition to the midchord vortex generators and dorsal fin discussed in our previous manuscript. A vertical stabilizer designed by ONERA was mounted on the NASA Common Research Model to computationally and experimentally investigate the performance of the flow control devices at several rudder deflection angles. A parametric study of the flow control devices was conducted using wind tunnel tests and computational fluid dynamics simulations, which were also used to understand how vortices generated around the flow control devices interact with the leading-edge separation vortex and boundary layer on the vertical stabilizer and rudder, and how the vortices improve the lateral performance of the vertical stabilizer. Wind tunnel tests were also used to validate the computational results.

关键词： Vertical Stabilisers Mean Aerodynamic Chord Boundary Layers computational fluid dynamics simulation Vortices Rudder Low Speed Wind Tunnel Vortex Generators Surface Streamlines Japan Aerospace Exploration Agency

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Numerical simulation of airflow and airborne pathogen transport in aircraft cabins: Dynamic Mesh Analyses

Numerical simulation of airflow and airborne pathogen transp...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Kotb, Hassan Khalil, Essam E. Cairo Univ Fac Engn Mech Power Dept Cairo Egypt

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

Contaminant transport in the aircraft cabin became one of the most vital issues that should be concerned, because there are over 4.6 billion passengers choose travelling by aircrafts, as they are safe, comfortable, and fast. In addition, aircrafts manufacturers aim to produce large aircrafts that are able to contain the highest number of passengers. Airborne diseases, for example, SARS and Influenza are considered the most fatal diseases, which can transport in the cabin rapidly, due to the large number of particles or droplets in one cough or sneeze as well as the velocity of these particles, as a consequence these characteristics, airborne pathogens such as cough and sneeze can spread and reach great number of passengers at one time. This study shows the result of simulation of cough droplets that produced from an infected moving passenger using computational fluid dynamics simulation (CFD) and dynamics mesh and discrete phase models in ANSYS FLUENT program, also it reveals the effects of these produced droplets on the other passengers inside the cabin. The results reveals that, cough droplet that produced during the movement of the passenger are extremely detrimental, as it could spread to a distance more than 4 meters along the cabin, moreover, it affected too many passengers in the cabin.

关键词： Commercial Aircraft Airflow computational fluid dynamics simulation Number of Particles Aircraft Cabin Environmental Control System Kinetic Energy Navier Stokes Equations Ventilation System Prandtl Numbers

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Control of Adverse Yaw During Roll for a Class of Optimal Lift Distributions

Control of Adverse Yaw During Roll for a Class of Optimal Li...

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AIAA Science and Technology Forum and Exposition (AIAA SciTech)

作者： Hunsaker, Douglas F. Montgomery, Zachary S. Joo, James J. Utah State Univ Mech & Aerosp Engn 4130 Old Main Hill Logan UT 84322 USA US Air Force Res Lab AFRL RQVS 2790 D St Wright Patterson AFB OH 45433 USA

ISBN: (数字)9781624105951

ISBN: (纸本)9781624105951

Lifting-line theory has formed the basis of our understanding of wing design for nearly a century. This theory has previously been used to develop a class of optimal lift distributions that minimize induced drag for finite wings under specific structural and aerodynamic constraints. This class of lift distributions was first introduced by Prandtl in 1933 and includes the elliptic lift distribution and the bell-shaped lift distribution, among others, as special cases. Here it is shown that, for all lift distributions in this class except the elliptic lift distribution, an antisymmetric twist distribution can be added to the wing to control the adverse yawing moment during roll. The requisite magnitude of this additional twist distribution depends on the prescribed yawing-moment sign and magnitude, and can be used to produce zero adverse yaw or even proverse yaw during roll. Of course, employing this methodology to control the roll-yaw coupling produces additional induced drag relative to the case without roll-yaw coupling control. This induced-drag penalty is studied in detail and shows that a symmetric lift distribution within this class can be selected to minimize induced drag for a desired roll-yaw coupling. Cases for roll initiation and steady rolling rate are both considered. Results can be applied to the design of morphing aircraft to minimize the use of a vertical control surface for yaw control.

关键词： Control Derivatives Roll Control Wing Planforms Aerodynamic Performance Tailless Aircraft Horizontal Stabilizers Roll Control System Lateral Stability Tapered Wings computational fluid dynamics simulation

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Flight-Relevant Gusts: Computation-Derived Guidelines for Micro Air Vehicle Ground Test Unsteady Aerodynamics

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JOURNAL OF AIRCRAFT 2021年第3期58卷 693-699页

作者： Mohamed, A. Watkins, S. Ol, M. V. Jones, A. R. RMIT Univ Sch Engn Melbourne Vic 3000 Australia Folderol LLC Xenia OH 45385 USA Univ Maryland Dept Aerosp Engn College Pk MD 20742 USA

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Assessment of occupant-behavior-based indoor air quality and its impacts on human exposure risk: A case study based on the wildfires in Northern California

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SCIENCE OF THE TOTAL ENVIRONMENT 2019年 686卷 1251-1261页

作者： Luo, Na Weng, Wenguo Xu, Xiaoyu Hong, Tianzhen Fu, Ming Sun, Kaiyu Tsinghua Univ Inst Publ Safety Res Dept Engn Phys Beijing 100084 Peoples R China Tsinghua Univ Beijing Key Lab City Integrated Emergency Respons Beijing 100084 Peoples R China Lawrence Berkeley Natl Lab Bldg Technol & Urban Syst Div Berkeley CA 94720 USA Tsinghua Univ Hefei Inst Publ Safety Res Hefei 320601 Anhui Peoples R China

The recent wildfires in California, U.S., have caused not only significant losses to human life and property, but also serious environmental and health issues. Ambient air pollution from combustion during the fires could increase indoor exposure risks to toxic gases and particles. further exacerbating respiratory conditions. This work aims at addressing existing knowledge gaps in understanding how indoor air quality is affected by outdoor air pollutants during wildfires-by taking into account occupant behaviors (e.g., movement, operation of windows and airconditioning) which strongly influence building performance and occupant comfort. A novel modeling framework was developed to simulate the indoor exposure risks considering the impact of occupant behaviors by integrating building energy and occupant behaviour modeling with computational fluid dynamics simulation. Occupant behaviors were found to exert significant impacts on indoor air flow patterns and pollutant concentrations, based on which, certain behaviors are recommended during wildfires. Further, the actual respiratory injury level under such outdoor conditions was predicted. The modeling framework and the findings enable a deeper understanding of the actual health impacts of wildfires, as well as informing strategies for mitigating occupant health risk during wildfires. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Human exposure risk Indoor air quality Occupant behavior Respiratory injury NAPA wildfire computational fluid dynamics simulation

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