A comprehensive experimental study was performed to investigate the effects of ice accretion on the aerodynamic performances and wake characteristics of a UAS propeller model under different icing conditions (i.e., rime vs. glaze). The experimental study was conducted in the unique Icing Research Tunnel available at Iowa State University (ISU-IRT). In addition to acquiring the key features of ice accretion on the rotating propeller blade using a “phase-locked” imaging technique, the wake characteristics of the rotating UAS propeller under the different icing conditions were also resolved by using the Particle Imaging Velocimetry (PIV) technique along with the time-resolved measurements of aerodynamic forces and power consumption of the UAS propeller model. Both “free-run” and “phaselocked” PIV measurements were performed on the propeller model at different stages of the icing experiments (i.e., before, during and after the dynamic icing processes) to provide both the instantaneous flow characteristics and the ensemble-averaged flow statistics (e.g., mean velocity, vorticity, and turbulence kinetic energy) in the wake of the rotating propeller model. It was found that while the rime ice accretion would closely follow the original profiles of the propeller blades, the glaze ice was formed into very irregular structures (e.g., “lobster-taillike” ice structures) that can significantly disturb the wake flow field of the rotating propeller model, generating the much larger and more complex vortices. Such complex large-scale vortices were found to enhance the turbulent mixing in the propeller wake and produce an evident velocity deficit channel around the outer board of the propeller blades, which provided direct evidences in elucidating the dramatic decrease in thrust generation and the significant increase in power consumption of the rotating propeller model in icing conditions. The findings derived from this study revealed the underlying mechanisms of the aerodynamic performance degradation of the iced UAS propeller, which is of significant importance for the development of innovative, effective anti-/de-icing strategies tailored for UAS icing mitigation and protection to ensure the safer and more efficient UAS operations in atmospheric icing conditions.
{"title":"Effects of Ice Accretion on the Aerodynamic Performance and Wake Characteristics of an UAS Propeller Model","authors":"Yang Liu, Linkai Li, Hui Hu","doi":"10.2514/6.2018-3496","DOIUrl":"https://doi.org/10.2514/6.2018-3496","url":null,"abstract":"A comprehensive experimental study was performed to investigate the effects of ice accretion on the aerodynamic performances and wake characteristics of a UAS propeller model under different icing conditions (i.e., rime vs. glaze). The experimental study was conducted in the unique Icing Research Tunnel available at Iowa State University (ISU-IRT). In addition to acquiring the key features of ice accretion on the rotating propeller blade using a “phase-locked” imaging technique, the wake characteristics of the rotating UAS propeller under the different icing conditions were also resolved by using the Particle Imaging Velocimetry (PIV) technique along with the time-resolved measurements of aerodynamic forces and power consumption of the UAS propeller model. Both “free-run” and “phaselocked” PIV measurements were performed on the propeller model at different stages of the icing experiments (i.e., before, during and after the dynamic icing processes) to provide both the instantaneous flow characteristics and the ensemble-averaged flow statistics (e.g., mean velocity, vorticity, and turbulence kinetic energy) in the wake of the rotating propeller model. It was found that while the rime ice accretion would closely follow the original profiles of the propeller blades, the glaze ice was formed into very irregular structures (e.g., “lobster-taillike” ice structures) that can significantly disturb the wake flow field of the rotating propeller model, generating the much larger and more complex vortices. Such complex large-scale vortices were found to enhance the turbulent mixing in the propeller wake and produce an evident velocity deficit channel around the outer board of the propeller blades, which provided direct evidences in elucidating the dramatic decrease in thrust generation and the significant increase in power consumption of the rotating propeller model in icing conditions. The findings derived from this study revealed the underlying mechanisms of the aerodynamic performance degradation of the iced UAS propeller, which is of significant importance for the development of innovative, effective anti-/de-icing strategies tailored for UAS icing mitigation and protection to ensure the safer and more efficient UAS operations in atmospheric icing conditions.","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121090694","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":"Quantification of Dynamic Glaze Icing Process over an Airfoil Surface by using a Digital Image Projection (DIP) Technique","authors":"Linyue Gao, Yang Liu, Hui Hu","doi":"10.2514/6.2018-3829","DOIUrl":"https://doi.org/10.2514/6.2018-3829","url":null,"abstract":"","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121391355","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":"GEM4D, a General vortex Encounter Model with 4 Degrees of Freedom: Formulation, Validation, and Use","authors":"D. Delisi, G. Greene, J. Tittsworth","doi":"10.2514/6.2018-3020","DOIUrl":"https://doi.org/10.2514/6.2018-3020","url":null,"abstract":"","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132669321","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":"Direct Numerical Simulation of a Thin Film Over a NACA 0012 Airfoil","authors":"J. Sakakeeny, S. McClain, Y. Ling","doi":"10.2514/6.2018-2857","DOIUrl":"https://doi.org/10.2514/6.2018-2857","url":null,"abstract":"","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130853175","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":"An Experimental Study on the Durability of a Hydro-/Ice-phobic Surface Coating for Aircraft Icing Mitigation","authors":"Zichen Zhang, Liqun Ma, Yang Liu, Hui Hu","doi":"10.2514/6.2018-3655","DOIUrl":"https://doi.org/10.2514/6.2018-3655","url":null,"abstract":"","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128435654","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":"Numerical Studies of Altitude Scaling for Ground Level Tests of Aeroengines with Ice Crystals","authors":"T. Currie","doi":"10.2514/6.2018-4132","DOIUrl":"https://doi.org/10.2514/6.2018-4132","url":null,"abstract":"","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127183340","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}
A computational icing risk analysis utilizing LEWICE3D was performed for the D8 Double Bubble aircraft. A variety of discrete drop sizes spanning the Appendix C and O regimes were simulated. For computational efficiency a 50-bin global discretization was produced and projected onto the distributions of interest, eliminating redundant simulations. The trajectory and impingement characteristics for discrete drop diameters were analyzed to help understand the behavior of the water drops in the presence of a complex flow field. The collection efficiency results for the discrete drop diameters were then weighted by their contributions to the total water content of six different continuous distributions and subsequently superposed to approximate these curves. Results indicate that significant variation in impingement exists as a function of drop diameter for complex wing body geometries, and that current discretization practices may be insufficient to accurately predict water collection on certain regions of the aircraft. Results also indicate that the Appendix O distributions, specifically those with considerable water content at large drops, generates water collection patterns that are markedly different from distributions representative of Appendix C.
{"title":"Computational Icing Risk Analysis of the D8 “Double Bubble” Aircraft","authors":"Christopher E. Porter, M. Potapczuk","doi":"10.2514/6.2018-2859","DOIUrl":"https://doi.org/10.2514/6.2018-2859","url":null,"abstract":"A computational icing risk analysis utilizing LEWICE3D was performed for the D8 Double Bubble aircraft. A variety of discrete drop sizes spanning the Appendix C and O regimes were simulated. For computational efficiency a 50-bin global discretization was produced and projected onto the distributions of interest, eliminating redundant simulations. The trajectory and impingement characteristics for discrete drop diameters were analyzed to help understand the behavior of the water drops in the presence of a complex flow field. The collection efficiency results for the discrete drop diameters were then weighted by their contributions to the total water content of six different continuous distributions and subsequently superposed to approximate these curves. Results indicate that significant variation in impingement exists as a function of drop diameter for complex wing body geometries, and that current discretization practices may be insufficient to accurately predict water collection on certain regions of the aircraft. Results also indicate that the Appendix O distributions, specifically those with considerable water content at large drops, generates water collection patterns that are markedly different from distributions representative of Appendix C.","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123897517","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}
Experiments were performed in the Icing Research Tunnel at NASA Glenn Research Center (GRC) to investigate the ice roughness and thickness evolution on a 152.4-cm (60-in.) chord business jet airfoil exposed to both Appendix C and Appendix O (SLD - Super-cooled Large Droplet) icing conditions. The resulting measurements demonstrate that the average non-dimensional roughness and the stagnation point thickness scalings are similar to those demonstrated on symmetric wings. However, the surface variations of roughness and thickness exhibit significant differences from those observed on symmetric airfoils. The source of the roughness and thickness differences is the result of surface pressure, velocity and temperature distribution differences from the suction to the pressure sides of the airfoil. LEWICE (LEWis ICE accretion program - software developed at NASA Lewis Research Center - former name of the GRC) simulations are used to further investigate the influences of local collection efficiency and the local freezing fraction on the resulting ice roughness and thickness spatial variations.
{"title":"Ice Roughness and Thickness Evolution on a Business Jet Airfoil","authors":"S. McClain, M. Vargas, J. Tsao, Andy P. Broeren","doi":"10.2514/6.2018-3014","DOIUrl":"https://doi.org/10.2514/6.2018-3014","url":null,"abstract":"Experiments were performed in the Icing Research Tunnel at NASA Glenn Research Center (GRC) to investigate the ice roughness and thickness evolution on a 152.4-cm (60-in.) chord business jet airfoil exposed to both Appendix C and Appendix O (SLD - Super-cooled Large Droplet) icing conditions. The resulting measurements demonstrate that the average non-dimensional roughness and the stagnation point thickness scalings are similar to those demonstrated on symmetric wings. However, the surface variations of roughness and thickness exhibit significant differences from those observed on symmetric airfoils. The source of the roughness and thickness differences is the result of surface pressure, velocity and temperature distribution differences from the suction to the pressure sides of the airfoil. LEWICE (LEWis ICE accretion program - software developed at NASA Lewis Research Center - former name of the GRC) simulations are used to further investigate the influences of local collection efficiency and the local freezing fraction on the resulting ice roughness and thickness spatial variations.","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123200215","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}
This work presents the results of an experimental study of ice particle impacts on a flat glass plate. The experiment was conducted at the Ballistics Impact Laboratory of NASA Glenn Research Center. The main objective of the experiment was to gain understanding about the modifications needed to the experimental configuration for a future parametric study at a larger range of values for particle diameters and other parameters. This was achieved by studying the effect of the velocity of an impacting ice particle on the post-impact fragment size and distribution for a reduced range of impacting particle diameters. Pre-impact particle diameter and velocity data were captured with a high-speed side camera. Post-impact fragment data were captured in a single frame with a 29-megapixel camera located above and normal to the target. Repeat runs were conducted for ice particles with diameters ranging from 1.7 to 2.9 millimeters, impacting at velocities between 39 and 98 meters per second. The fragment areas were measured, and the corresponding equivalent diameters and histogram distributions were calculated. Analysis of the data showed that the average equivalent diameter for the fragments in a run was an order of magnitude smaller than the diameter of the impacting ice particle. The histograms for equivalent diameter distribution were non-normal with long tails, with most of the fragments having equivalent diameters concentrated toward the minimum value of the fragment size that could be resolved. Factors affecting the accuracy of the data during the digital imaging analysis were identified. Needed modifications to the setup to handle small size ice particles and other testing conditions were also identified. at a given pressure Test = A series of experimental runs at the same tank pressure and with similar ice particle diameter for ice particles of similar diameter. Each test contained 10 runs. Tests were conducted for tank pressures of 3, 5, 7, 9, 11, 13, 15, 17, and 20 psi. At each pressure, for each run, the image of the expanding fragments was segmented, and the area of each fragment was calculated. For each fragment, the diameter of a circle with the same area was calculated and called “the equivalent diameter”. For a given run, the average of the fragment
{"title":"Fragment Size Distribution for Ice Particle Impacts on a Glass Plate","authors":"M. Vargas, C. Ruggeri, J. M. Pereira, D. Revilock","doi":"10.2514/6.2018-4225","DOIUrl":"https://doi.org/10.2514/6.2018-4225","url":null,"abstract":"This work presents the results of an experimental study of ice particle impacts on a flat glass plate. The experiment was conducted at the Ballistics Impact Laboratory of NASA Glenn Research Center. The main objective of the experiment was to gain understanding about the modifications needed to the experimental configuration for a future parametric study at a larger range of values for particle diameters and other parameters. This was achieved by studying the effect of the velocity of an impacting ice particle on the post-impact fragment size and distribution for a reduced range of impacting particle diameters. Pre-impact particle diameter and velocity data were captured with a high-speed side camera. Post-impact fragment data were captured in a single frame with a 29-megapixel camera located above and normal to the target. Repeat runs were conducted for ice particles with diameters ranging from 1.7 to 2.9 millimeters, impacting at velocities between 39 and 98 meters per second. The fragment areas were measured, and the corresponding equivalent diameters and histogram distributions were calculated. Analysis of the data showed that the average equivalent diameter for the fragments in a run was an order of magnitude smaller than the diameter of the impacting ice particle. The histograms for equivalent diameter distribution were non-normal with long tails, with most of the fragments having equivalent diameters concentrated toward the minimum value of the fragment size that could be resolved. Factors affecting the accuracy of the data during the digital imaging analysis were identified. Needed modifications to the setup to handle small size ice particles and other testing conditions were also identified. at a given pressure Test = A series of experimental runs at the same tank pressure and with similar ice particle diameter for ice particles of similar diameter. Each test contained 10 runs. Tests were conducted for tank pressures of 3, 5, 7, 9, 11, 13, 15, 17, and 20 psi. At each pressure, for each run, the image of the expanding fragments was segmented, and the area of each fragment was calculated. For each fragment, the diameter of a circle with the same area was calculated and called “the equivalent diameter”. For a given run, the average of the fragment","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123145787","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 Guide Creating SAE AS5562 Ice Crystal, Mixed Phase and Rain Conditions in a Wind Tunnel Environment","authors":"C. Clark, D. Orchard, G. Chevrette","doi":"10.2514/6.2018-3833","DOIUrl":"https://doi.org/10.2514/6.2018-3833","url":null,"abstract":"","PeriodicalId":419456,"journal":{"name":"2018 Atmospheric and Space Environments Conference","volume":"abs/2302.13353 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124021868","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}
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