AIAA Scitech 2021 Forum最新文献

{"title":"Experimental Characterization of the Dimensional Stability of Deployable Composite Booms During Stowage","authors":"Joshua E. Salazar, Juan M. Fernandez","doi":"10.2514/6.2021-0195","DOIUrl":"https://doi.org/10.2514/6.2021-0195","url":null,"abstract":"Thin-ply carbon fiber reinforced polymer materials offer the opportunity to create long thin-shell booms with high strength to weight ratios. These booms can be rolled up and stowed in small volumes to be later deployed. These features make them ideal for use in gossamer solar sails as well as other deployable space structures. It has been observed that stowing the booms in rolled-up configurations can cause time dependent deformations. A comprehensive understanding of the detrimental effects of stowing the coiled booms is necessary to implement these structures in spaceflight missions. During stowage inside the spacecraft, the boom is subjected to a constant deformation/strain that causes it to relax over time, measurable by a decrease in stress. Using large deformation bending tests the complete fold-stow-unfold-recover cycle of thin-laminate candidates for the rollable booms is characterized. Further bending and stowage testing is done at the boom level. The results from this test campaign will be used to evaluate the dimensional stability of deployable booms made from thin-ply composites that exhibit viscoelastic behavior and calibrate and validate numerical finite element models.","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125468401","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":"Rapid Aero Modeling for Urban Air Mobility Aircraft in Wind-Tunnel Tests","authors":"P. Murphy, Benjamin M. Simmons, David B. Hatke, Ronald C. Busan","doi":"10.2514/6.2021-1644","DOIUrl":"https://doi.org/10.2514/6.2021-1644","url":null,"abstract":"Rapid Aero Modeling (RAM) applied to wind tunnel testing, RAM-T, is an approach to efficiently and automatically obtain aerodynamic models during testing. The approach saves time and resources by responding to the demand for experimental efficiency and model fidelity. Motivation for this demand is more acute when investigating a class of vehicles categorized as Urban Air Mobility (UAM) aircraft where many features from both aircraft and rotorcraft are present. RAM-T provides a feedback loop around the test facility to guide the test toward high-fidelity, statistically rigorous aircraft models. The general RAM approach is applicable to computational or physical experiments. It combines concepts from design of experiment theory and aircraft system identification theory that allow the user the freedom to choose, in advance of the test, a specific level of fidelity in terms of prediction error. RAM only collects data required to meet the user-specified fidelity and fidelity is only limited by the facility and test article capabilities. This paper presents results from tests conducted for development of an automated RAM-T technology. The results highlight some of the unique features of RAM applied to eVTOL configurations","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115966628","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":"Lessons Learned from Large-Scale Aerospace Structural Testing","authors":"A. Lovejoy, D. Jegley, M. Hilburger, A. Przekop","doi":"10.2514/6.2021-1619","DOIUrl":"https://doi.org/10.2514/6.2021-1619","url":null,"abstract":"Large-scale testing of aerospace structures is frequently the final step in a development project to validate the structural performance, and that step typically involves a large cost and time investment. To ensure that the testing provides the required data, avoiding errors that can result in an unsuccessful test and failure to meet objectives is critical. Five lessons learned are presented herein to provide insight to those conducting large-scale tests to help them avoid known pitfalls that may result in an unsuccessful test. Five large-scale tests are described, and they include two composite wing tests, a full-scale 27.5-ft-diam metallic barrel test, an 8-ft-diam metallic barrel test, and a composite hybrid-wing–body center section test. Problems identified during the testing and mitigation approaches to solve the problems are presented, and then the lessons learned are identified and discussed.","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114374811","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":"Performance Enhancement by Tandem Wings Interaction of CoFlow Jet Aircraft","authors":"Yan Ren, Gecheng Zha","doi":"10.2514/6.2021-1823","DOIUrl":"https://doi.org/10.2514/6.2021-1823","url":null,"abstract":"This paper numerically studies the cruise efficiency enhancement by 3D tandem wings interaction for a CoFlow Jet (CFJ) aerial vehicle at cruise Mach number of 0.17. The simulations employ 3D RANS solver with Spalart-Allmaras (S-A) turbulence model, 3rd order WENO scheme for the inviscid fluxes, and 2nd order central differencing for the viscous terms. The aerodynamic performance, energy expenditure, and flow field of the tandem wing propeller-CFJ aircraft are investigated. Each of the tandem wings has a propeller mounted above the wing suction surface to reduce the CFJ power required. The front wing is smaller with the planform area 1/3 of that of the rear wing. Both wings have the same chord. The aspect ratio for the front wing is 3.56 and 10.68 for the rear wing. The area averaged aspect ratio of the aircraft is 8.9. The study holds a constant optimal angle of attack (AoA) of 5◦ for the front wing and has the AoA of the rear wing at 5◦, 10◦, and 15◦. The two wings are separated by one chord length in the stream-wise direction and are aligned in the same transverse position. Such a configuration allows the rear wing to capture the tip vortex of the front wing on the suction surface with its low pressure. This vortex capturing mechanism enhances the lift of the rear wing significantly attributed to the low pressure of the tip vortex core and the upwash the vortex generates. The optimal aerodynamic efficiency and productivity efficiency of the tandem wing vehicle system are obtained when the AoA of the rear wing is at 10◦. When the AoA of the rear wing is increased from 5◦ to 10◦, the increased circulation of the larger rear wing dominates the flow field. The induced circulation of the rear wing with a stronger propeller strength create an upwash favorable to the front wing, which produces an aerodynamic ratio of CL/CD of 21.85 and the corrected aerodynamic efficiency CL/(CD)c of 14.39. These are extraordinarily high merit results for the small front wing with a small aspect ratio of 3.56. The corrected aerodynamic efficiency CL/(CD)c for the whole vehicle is 14.27 with a lift coefficient of 1.6, which result in a corrected productivity efficiency C L/(CD)c for the whole vehicle of 22.82. The overall vehicle efficiency are excellent due to the high vehicle cruise lift coefficient of 1.6 and corrected aerodynamic efficiency of 14.27 for a moderate aspect ratio of 8.9. The cruise lift coefficient of 1.6 attributed to the CFJ active flow control is almost 3 times greater than that of conventional subsonic aircraft, which would be stalled at such a high lift coefficient or severely penalized by its excessive drag. This study indicates that the two tandem wings benefit each other. The front wing tip vortex enhances the lift of the rear wing and the rear wing’s high lift and circulation increase the front wing’s efficiency due to the upwash. The tandem wing configuration presented in this paper is not optimized and could be a start for a new area of air","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117132663","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":"Heteroscedastic Gaussian Process Regression using Nearest Neighbor Point Estimates","authors":"M. D. Robani, P. S. Palar, L. Zuhal","doi":"10.2514/6.2021-1589","DOIUrl":"https://doi.org/10.2514/6.2021-1589","url":null,"abstract":"","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123117355","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":"Experimental Investigation of Atmospheric Induced Beam Jitter","authors":"M. Kalensky, E. Jumper, S. Gordeyev, A. Archibald, Matthew R. Kemnetz","doi":"10.2514/6.2021-0334","DOIUrl":"https://doi.org/10.2514/6.2021-0334","url":null,"abstract":"","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124456258","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":"Wall-modeled LES of flow over a Gaussian bump","authors":"Prahladh S. Iyer, M. Malik","doi":"10.2514/6.2021-1438","DOIUrl":"https://doi.org/10.2514/6.2021-1438","url":null,"abstract":"","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"106 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123975908","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":"Experimental Investigation of Aerodynamic Interactions During Shipboard Launch & Recovery of Unconventional UAVs","authors":"N. Bi, A. Schwartz, Jared Soltis, Kevin Kimmel, A. Sydney","doi":"10.2514/6.2021-1536","DOIUrl":"https://doi.org/10.2514/6.2021-1536","url":null,"abstract":"","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125413956","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":"A Phenomenological Model of Nanosecond Pulsed Discharge Effects on Non-reacting Flow in a 3-D Swirl Stabilized Burner","authors":"J. Strafaccia, S. Bane","doi":"10.2514/6.2021-1973","DOIUrl":"https://doi.org/10.2514/6.2021-1973","url":null,"abstract":"","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126446051","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":"Scalable Domain Decomposition for Large-Scale Multibody-3D Finite Element Structures","authors":"Ravi T. Lumba, A. Datta","doi":"10.2514/6.2021-1078","DOIUrl":"https://doi.org/10.2514/6.2021-1078","url":null,"abstract":"A mesh partitioner was developed for large-scale 3D rotor structural dynamic models containing higher-order 3D finite elements and multibody joints. A parallel iterative substructuring solver was built to operate on the partitioned data structures. The algorithmic scalability of the solver was demonstrated on three sample problems of progressively increasing complexity; an elementary uniform beam, a real rotor blade - the NASA TRAM (1/4 scale V-22 model blade), and the full TRAM blade and hub assembly containing four flexible parts connected using six joints. The key conclusion is that a multibody blade and hub assembly can be partitioned and solved in a parallel and scalable manner. Rotor structures of up to 6.6 million degrees of freedom are solved on up to 2048 processors with detailed studies of scalability and efficiency. The uniform cantilevered beam is able to achieve a speedup of 1000 times, while the realistic rotor is able to achieve a speedup of over an order of magnitude, reducing the computational time to a matter of seconds. The use of the specialized mesh partitioner, with a robust corner node selection strategy, is key to minimizing computational time.","PeriodicalId":165313,"journal":{"name":"AIAA Scitech 2021 Forum","volume":"52 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130113368","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}