Proceedings of the Vertical Flight Society 78th Annual Forum最新文献

{"title":"CFD Simulation of Flow Around ROBIN-Mod7 Fuselage with PSP Rotor Using an Immersed Boundary Method","authors":"H. Park, D. Linton, B. Thornber","doi":"10.4050/f-0078-2022-17504","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17504","url":null,"abstract":"\u0000 Computational fluid dynamics simulations of the flow around the ROBIN-mod7 fuselage with PSP rotor are conducted using an immersed boundary method and an actuator surface model in OpenFOAM. The ROBIN-mod7 fuselage is represented by the immersed boundary method, while the unsteady rotor is modeled using the actuator surface model. The integration of the immersed boundary method and actuator surface model is straightforward; there is no fundamental reason to be conflicted with each other in both theory and practice. A comprehensive analysis of the generic helicopter configuration is carried out for the hovering flight condition; the isolated fuselage is simulated to provide its baseline aerodynamics, and the isolated rotor and rotor-fuselage cases are studied to measure the rotor performance in hover and the fuselage effect on the performance. The validation of each test case is conducted against both experimental measurements and computational data from the literature. The surface pressure data from the isolated fuselage case shows good agreement with the experimental measurements. Also, the rotor performance predicted on the isolated and installed rotors (rotor-fuselage) has excellent agreement with the reference data; in particular, the performance data on the installed rotor agrees with the experimental data better than the previous numerical study does. The fuselage effect has been analyzed by comparing the isolated rotor and rotor-fuselage data sets. The computational effort for different grid levels of each test case is provided. Overall, the results have demonstrated an equivalent level of accuracy compared to the previous high-fidelity simulation results at their fraction of setup and computational expenses.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130703406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tolerance Relief on Transmissions Castings for Producibility","authors":"Brad Gimbutis, Griffin Palmer, Justin Beardsley, Holly Quinn","doi":"10.4050/f-0078-2022-17569","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17569","url":null,"abstract":"\u0000 Helicopter gearbox transmission castings must be designed for adequate strength, adequate stiffness for gear meshes and flight loads, clean-up of all machined surfaces, adequate edge distance for all clamped connections and minimum weight. Castings manufacturers generally request relatively large tolerances due to the nature of the casting processes in the order of +/- 0.100 inch while designers will require casting tolerances in the order of +/- 0.030 inch for cast surfaces. Excess casting material can lead to assembly interferences and excess weight while insufficient material can lead to thin wall conditions, lack of damage repair capability and potential performance issues. This paper describes how skewed (unilateral or unequally disposed) casting tolerances can eliminate casting rejections, eliminate Material Review Board (MRB) delays, eliminate reworks, ensure proper performance, and have negligible impact on weight.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130950164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aeroacoustic Prediction and Validation of Variable RPM Rotors and Rotor-Airframe Interactions for Advanced Air Mobility Applications","authors":"Mrunali Botre, K. Brentner, D. Wachspress, Zexu Feng","doi":"10.4050/f-0078-2022-17430","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17430","url":null,"abstract":"\u0000 Aeroacoustic prediction of the tonal noise sources for rotors operating with time-varying rotor rotation rate (RPM) is explored. Enhancements to the CHARM analysis and CHARM/PSU-WOPWOP interface software are described that are required to support acoustic predictions of time-varying RPM multiple rotor and rotor + strut configurations. Predictions are compared with acoustic test data from (Ref. 1) and (Ref. 2) for both constant and time-varying RPM. The configuration with time-varying RPM was considered to understand the tonal noise sources with a focus on loading noise. The effect of change in RPM on aerodynamic interaction between rotor and strut and its effect on loading noise was studied. A comparison between NASA wind tunnel test data and predictions for an isolated ideally twisted rotor is carried out with time-varying rotor RPM data. Sound pressure spectrum plots are generated for raw test data, filtered test data (frequency range 250-1500 Hz), and acoustic pressure time history to perform validation at in-plane and out-of-plane microphones.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128827451","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Analysis of Energy Absorbing Subfloor Concepts to Improve eVTOL Crashworthiness","authors":"J. Putnam, J. Littell, M. Reaves, N. Gardner","doi":"10.4050/f-0078-2022-17501","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17501","url":null,"abstract":"\u0000 To help ensure safe transportation within electric Vertical Take-off and Landing (eVTOL) vehicles the National Aeronautics and Space Administration (NASA) has been developing novel energy absorbing (EA) design technologies to improve crashworthiness within the unique design constraints of these vehicles. As part of this effort, a series of lightweight energy absorbing subfloor concepts were developed for potential use within eVTOL vehicle design. The capability of the subfloor designs was first evaluated through finite element (FE) model simulation in both component and vehicle level impact conditions. Knowledge gained from these analyses were used to iterate upon the design prior to fabrication. Fabrication and testing of the subfloor designs has begun and will be used to verify predicted capability. Results from FE model analysis was used to down select to a final subfloor geometry for additional component level optimization and full-scale test validation. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"307 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115226023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced Thermal Analysis Methodologies to Support eVTOL Propulsion System Optimization","authors":"L. Rogers, T. Holdstock","doi":"10.4050/f-0078-2022-17539","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17539","url":null,"abstract":"\u0000 eVTOL vehicles have seen rapid advancements in electric propulsion technologies supported by complex high-fidelity simulations that allow subsystem performance to be maximized. Optimizing subsystem performance can improve propulsion system power density, especially through improved cooling. However, current work on holistic system level approach to eVTOL propulsion system designs [1,2] can benefit from earlier consideration of the interactions between inverter, motor, transmission, and thermal management systems. This can give a better understanding of the trade-offs between increasing power density and more complex, active cooling systems. These trade-offs must be understood as active cooling elements can lead to additional redundancy and certification requirements, which can increase the time-to-market in a highly competitive environment. This paper proposes an approach that quantifies these trade-offs early in the design process, so that the right propulsion system can be brought to market in the right timeframe. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124442779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved Strain Gage Instrumentation Strategies for Rotorcraft Blade Measurements","authors":"T. S. Davis","doi":"10.25777/Z643-1G53","DOIUrl":"https://doi.org/10.25777/Z643-1G53","url":null,"abstract":"In this presentation, a new strategy is presented to wire, calibrate, and measure strain gages for rotor blade testing that will provide more information and is robust to individual gage loss. The additional information can be used in several ways. including reducing redundancy, offering rapid identification of damage locations, and in some cases reducing risk allowing tests to continue to collect calibrated data after one or more sensors have failed. This strategy replaces the classical four-gage full Wheatstone bridge with four separately wired quarter bridges that are combined into a full bridge in the data acquisition system using a calculated channel. This strain gaging concept also provides the engineer with data from the four individual stresses, as well as the calibrated full bridge output that has been converted into engineering units.","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114598721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomimetic Adaptive Airframe Technologies (BAAT) for Rotorcraft Design and Optimization","authors":"A. Davis, Bochan Lee, Moble Benedict, D. Hartl","doi":"10.4050/f-0078-2022-17493","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17493","url":null,"abstract":"\u0000 Mission-adaptive aerostructural design considers the alteration of structural geometries to improve multi-objective performance across multiple aerodynamic environments associated with flight conditions derived from specific mission profiles. To accomplish this, adaptive structures design requires evaluating the aerostructural responses for each possible geometry to determine the optimal configuration for each mission stage. This work develops a mission-driven design framework combining aerodynamic, structural, mission, and optimization computational tools to design and optimize adaptive vertical lift aerostructures. Aerodynamic conditions and vehicle properties are driven or defined by mission requirements, where a mission is defined as a sequence of specified flight phases (inputs) with a unique set of performance objectives (outputs). Aerodynamic and structural analysis tools iteratively trim the vehicle for each mission phase while considering desired geometric changes, viable actuation methods, and actuator sizing required. Together these comprise a complete structural description. Preferred geometries for each mission phase are then determined via optimization to improve performance metrics defined by mission objectives and requirements. The computational framework searches algorithmically for structural configurations that improve mission-driven objectives based on trim flight for each mission phase using a novel algorithm to consider both adaptive and fixed design variable selection to effectively solve this complex design problem. It will be shown that both the optimal placement of adaptive structures and levels of morphing can be determined concurrently via a novel optimization and postprocessing procedure, leading to mission-wide performance improvements (in this case, reduced required power) not possible with static structures.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114532792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Helicopter Noise Source Separation Using an Order Tracking Filter","authors":"Joel Sundar Rachaprolu, Eric Greenwood","doi":"10.4050/f-0078-2022-17433","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17433","url":null,"abstract":"Due to the importance of understanding the aeroacoustics of rotorcraft with continually changing noise sources, this paper presents a new technique for source separation from ground-based acoustic measurements. The source separation process is based on combining a time-domain de-Dopplerization method with the Vold-Kalman (VK) order tracking filter approach. This process can extract rotor harmonic noise even when the sources are continuously changing with time, including impulsive events such as Blade Vortex Interaction (BVI) noise. The advantage of this approach over traditional methods such as harmonic averaging is that the phase and amplitude relationship of acoustic signals is preserved throughout the extraction process. The approach is applied to the measured acoustic data from a Bell 430 helicopter. The measured data were separated into main rotor harmonic, tail rotor harmonic, and broadband residual components. For steady-state conditions, the extracted components could be de-propagated to form acoustic spheres showing the directivity of the separated main and tail rotor components. The source separation process was also applied to a maneuvering flight condition. Each component has different pulse shapes and directivity trends, consistent with aeroacoustic theory.","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"471 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117039730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced Seat Belt System for Occupant Restraint","authors":"Marvin K. Richards","doi":"10.4050/f-0078-2022-17502","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17502","url":null,"abstract":"\u0000 Current passive occupant restraints do not adequately restrict upper torso/head motion during a crash, especially with a combined forward and vertical acceleration component. The belt geometry of conventional webbing restraints allows the upper torso to rotate forward, increasing the probability of secondary impacts. In addition to the suboptimal belt geometry issues, some occupants are not familiar with the current 4-point and 5-point restraints. Safe, Inc. has developed a passive restraint system with improved belt routing geometry to reduce the occupant's motion and resulting injury risk. The restraint supplements the familiar automotive 3-point restraint system with a second, mirror image diagonal shoulder belt to provide upper torso restraint in all directions. It is intuitive to don with minimal installation instruction to encourage more frequent and proper use. The restraint would be beneficial to all vehicle types and is well suited for the emerging Urban Air Mobility (UAM) platforms.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117075518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Safety of Advanced Air Mobility and The Effects of Wind in the Urban Canyon","authors":"Sharon Schajnoha, Hali Barber, G. Larose, Maryam Al-Labbad, A. Wall","doi":"10.4050/f-0078-2022-17611","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17611","url":null,"abstract":"\u0000 The safe integration of vertical takeoff and landing aircraft (VTOLs) into an urban setting requires careful consideration of the effects of the wind flows through the urban canyon, which are complex and cannot be predicted with the reliability level necessary to enable safe operations. The assessment of wind in the urban canyon is critical to the siting and design of vertiports and safe operations of VTOLs. \u0000\u0000Vertiport design guidance related to the effects of wind flows in the urban canyon is limited and draws from helipad design guidance. The guidance recommends that wind conditions be assessed across a vertiport, but the guidance does not suggest how the study should be conducted nor does it provide design thresholds for wind. \u0000\u0000RWDI, the National Research Council Canada and Transport Canada have joined forces to identify and study the wind characteristics that would be important for the aerodynamic performance of VTOL and how these characteristics would be influenced by buildings and structures in the urban environment. In the framework of this research effort, an experimental approach was developed, centered on several sites in Canadian cities, representing a range of urban densities and surrounding topographies, as wind conditions are highly dependent on the built environment, including building footprint, building features, combinations of buildings and the local climatology. \u0000\u0000The work involved a quantitative approach in which physical models of several urban sites were built, instrumented and tested in boundary layer wind tunnels. In the wind tunnel experiments, \"red flag\" wind conditions were identified and measured. Detailed data capturing these flow features were collected around roof tops of lower and taller buildings, representing prospective vertiport locations and along prospective flight paths. \u0000\u0000This paper provides the details of the wind tunnel testing conducted for one of the urban sites; a site with an existing helipad at a hospital and a low-rise parking garage. The wind tunnel measurements were compared to published helipad design thresholds and combined with long term meteorological conditions representative of the site to determine how often vertiport operations will be limited by unfavourable urban wind conditions on an annual basis and by season. The wind tunnel study provides a case study and demonstrates how to evaluate the safety of a vertiport now, based on limited availability of VTOL aerodynamic performance capabilities and into the future as more information becomes available on VTOL performance in turbulent winds. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117166626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}