{"title":"Model Development for a Comparison of VTOL and STOL Electric Aircraft Using Geometric Programming","authors":"C. Courtin, R. Hansman","doi":"10.2514/6.2019-3477","DOIUrl":"https://doi.org/10.2514/6.2019-3477","url":null,"abstract":"","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128704250","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}
M. Meliani, N. Bartoli, T. Lefebvre, M. Bouhlel, J. Martins, J. Morlier
Predictions and design engineering decisions can be made using a variety of informa- tion sources that range from experimental data to computer models. These information sources could consist of different mathematical formulations, different grid resolutions, dif- ferent physics, or different modeling assumptions that simplify the problem. This leads to information sources with varying degrees of fidelity, each with an associated accuracy and querying cost. In this paper, we propose a novel and flexible way to use multi-fidelity informa- tion sources optimally in the context of airfoil shape optimization using both Xfoil and ADflow. The new developments are based on Bayesian optimization and kriging metamodeling and allow the aerodynamic optimization to be sped up. In a constrained optimization example with 15-design variables problem, the proposed approach reduces the total cost by a factor of two compared to a single Bayesian based fidelity optimization and by a factor of 1.5 compared to sequential quadratic programming.
{"title":"Multi-fidelity efficient global optimization: Methodology and application to airfoil shape design","authors":"M. Meliani, N. Bartoli, T. Lefebvre, M. Bouhlel, J. Martins, J. Morlier","doi":"10.2514/6.2019-3236","DOIUrl":"https://doi.org/10.2514/6.2019-3236","url":null,"abstract":"Predictions and design engineering decisions can be made using a variety of informa- tion sources that range from experimental data to computer models. These information sources could consist of different mathematical formulations, different grid resolutions, dif- ferent physics, or different modeling assumptions that simplify the problem. This leads to information sources with varying degrees of fidelity, each with an associated accuracy and querying cost. In this paper, we propose a novel and flexible way to use multi-fidelity informa- tion sources optimally in the context of airfoil shape optimization using both Xfoil and ADflow. The new developments are based on Bayesian optimization and kriging metamodeling and allow the aerodynamic optimization to be sped up. In a constrained optimization example with 15-design variables problem, the proposed approach reduces the total cost by a factor of two compared to a single Bayesian based fidelity optimization and by a factor of 1.5 compared to sequential quadratic programming.","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"151 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115104951","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}
Advancing towards the correct modeling and subsequent understanding of laminar-toturbulent transition during atmospheric reentry is paramount for the future of aerospace technology. The coexistence of multiple physical phenomena and the grand amount of conditioning factors require the progressive extension of the applicability capabilities of the theoretical models. Past efforts have been mostly dedicated to investigate high-temperature and non-equilibrium effects using parallel stability theories. However, the implications of coupling these thermochemical phenomena with non-parallelism remains uncertain. Advanced state of the art thermodynamic and transport models are employed both in parallel and weakly non-parallel stability theories (LST and LPSE). A parametric study about the influence of nonlocal effects under different re-entry conditions and flow assumptions (i.e. CPG, TPG, CNE and LTE) showed that non-parallel effects stabilize/destabilize the boundary-layer, depending on the altitude and independently from the gas model employed. Particularly, they lead to a stronger destabilization of the 2nd Mackmode at the earliest points of the atmospheric re-entry flight envelope, reducing their effect until being weakly stabilizing at the lowest altitudes. Drastic N factor increments occurred assuming LTE, due to the presence of unstable supersonic modes, promoted by the boundary-layer cooling, caused by the intense chemical activity.
{"title":"Weak Non-Parallel Effects on Chemically Reacting Hypersonic Boundary Layer Stability","authors":"L. Zanus, F. M. Miró, F. Pinna","doi":"10.2514/6.2019-2853","DOIUrl":"https://doi.org/10.2514/6.2019-2853","url":null,"abstract":"Advancing towards the correct modeling and subsequent understanding of laminar-toturbulent transition during atmospheric reentry is paramount for the future of aerospace technology. The coexistence of multiple physical phenomena and the grand amount of conditioning factors require the progressive extension of the applicability capabilities of the theoretical models. Past efforts have been mostly dedicated to investigate high-temperature and non-equilibrium effects using parallel stability theories. However, the implications of coupling these thermochemical phenomena with non-parallelism remains uncertain. Advanced state of the art thermodynamic and transport models are employed both in parallel and weakly non-parallel stability theories (LST and LPSE). A parametric study about the influence of nonlocal effects under different re-entry conditions and flow assumptions (i.e. CPG, TPG, CNE and LTE) showed that non-parallel effects stabilize/destabilize the boundary-layer, depending on the altitude and independently from the gas model employed. Particularly, they lead to a stronger destabilization of the 2nd Mackmode at the earliest points of the atmospheric re-entry flight envelope, reducing their effect until being weakly stabilizing at the lowest altitudes. Drastic N factor increments occurred assuming LTE, due to the presence of unstable supersonic modes, promoted by the boundary-layer cooling, caused by the intense chemical activity.","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"176 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116040619","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}
Yibin Zhang, Daniel R. Richardson, S. Beresh, Katya M. Casper, M. Soehnel, J. Henfling, R. Spillers
{"title":"Correction: Hypersonic wake measurements behind a slender cone using FLEET velocimetry","authors":"Yibin Zhang, Daniel R. Richardson, S. Beresh, Katya M. Casper, M. Soehnel, J. Henfling, R. Spillers","doi":"10.2514/6.2019-3381.C1","DOIUrl":"https://doi.org/10.2514/6.2019-3381.C1","url":null,"abstract":"","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115594397","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":"Global instability analysis of a boundary layer flow over a small cavity","authors":"M. Mathias, M. Medeiros","doi":"10.2514/6.2019-3535","DOIUrl":"https://doi.org/10.2514/6.2019-3535","url":null,"abstract":"","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123131838","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}
Nonlinear development of the Görtler instability over a concave surface gives rise to a highly distorted inflectional flow field in the boundary layer that leads to both wall-normal and spanwise gradients in the flow. Such nonlinear structures are susceptible to strong, high-frequency secondary instabilities that may lead to the onset of laminar-turbulent transition. The present numerical study uses direct numerical simulations and linear secondary instability theory to investigate finite amplitude Görtler vortices and their secondary instability characteristics, respectively, in the hypersonic flow over an axisymmetric cone with a concave aft body. To complement previous studies in the literature wherein the Görtler instability was usually studied for a flat plate and initiated at some upstream location by imposing an eigenfunction as the inflow condition or by blowing and suction at the wall, the present investigation is focused on fully realizable Görtler instability that is excited by an azimuthally periodic array of surface protuberances. Furthermore, while the previous work had mostly focused on the secondary instability of Görtler vortices with cross-plane velocity contours that resembled bell-shaped structures, the present results confirm that fully developed mushroom structures also exist in the hypersonic regime when the Görtler vortex amplitude is sufficiently large. Computations further reveal that the dominant modes of secondary instability in these mushroom-shaped structures correspond to an antisymmetic (i.e., sinuous) “stem” mode that concentrates within the strong, nearly wall-normal internal shear layers surrounding the stem regions underneath the caps of the mushroom structures. Additionally, there exist a multitude of other significantly unstable secondary instability modes of both symmetric and antisymmetric types. Analogous to the secondary instability of crossflow vortices in hypersonic flows, secondary instability modes originating from the Mack mode instability play an important role during the nonlinear breakdown process.
{"title":"Nonlinear Görtler Vortices and Their Secondary Instability in a Hypersonic Boundary Layer","authors":"Fei Li, Meelan Choudhari, P. Paredes","doi":"10.2514/6.2019-3216","DOIUrl":"https://doi.org/10.2514/6.2019-3216","url":null,"abstract":"Nonlinear development of the Görtler instability over a concave surface gives rise to a highly distorted inflectional flow field in the boundary layer that leads to both wall-normal and spanwise gradients in the flow. Such nonlinear structures are susceptible to strong, high-frequency secondary instabilities that may lead to the onset of laminar-turbulent transition. The present numerical study uses direct numerical simulations and linear secondary instability theory to investigate finite amplitude Görtler vortices and their secondary instability characteristics, respectively, in the hypersonic flow over an axisymmetric cone with a concave aft body. To complement previous studies in the literature wherein the Görtler instability was usually studied for a flat plate and initiated at some upstream location by imposing an eigenfunction as the inflow condition or by blowing and suction at the wall, the present investigation is focused on fully realizable Görtler instability that is excited by an azimuthally periodic array of surface protuberances. Furthermore, while the previous work had mostly focused on the secondary instability of Görtler vortices with cross-plane velocity contours that resembled bell-shaped structures, the present results confirm that fully developed mushroom structures also exist in the hypersonic regime when the Görtler vortex amplitude is sufficiently large. Computations further reveal that the dominant modes of secondary instability in these mushroom-shaped structures correspond to an antisymmetic (i.e., sinuous) “stem” mode that concentrates within the strong, nearly wall-normal internal shear layers surrounding the stem regions underneath the caps of the mushroom structures. Additionally, there exist a multitude of other significantly unstable secondary instability modes of both symmetric and antisymmetric types. Analogous to the secondary instability of crossflow vortices in hypersonic flows, secondary instability modes originating from the Mack mode instability play an important role during the nonlinear breakdown process.","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116967277","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}
M. Bolinches-Gisbert, R. Corral, F. Gisbert, A. Sotillo
{"title":"Correction: Implicit Large Eddy Simulation of Low Pressure Turbine Airfoils Using a High Order Navier-Stokes Solver","authors":"M. Bolinches-Gisbert, R. Corral, F. Gisbert, A. Sotillo","doi":"10.2514/6.2019-2840.C1","DOIUrl":"https://doi.org/10.2514/6.2019-2840.C1","url":null,"abstract":"","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116976372","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":"F-35 High Angle of Attack Flight Control Development and Flight Test Results","authors":"Dan Canin","doi":"10.2514/6.2019-3227","DOIUrl":"https://doi.org/10.2514/6.2019-3227","url":null,"abstract":"","PeriodicalId":384114,"journal":{"name":"AIAA Aviation 2019 Forum","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117214489","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}