{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T11:40:06Z","timestamp":1760010006268,"version":"build-2065373602"},"publisher-location":"400 Commonwealth Drive, Warrendale, PA, United States","reference-count":8,"publisher":"SAE International","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<div class=\"section abstract\"><div class=\"htmlview paragraph\">Although CFD is considered a well-established tool in the\ndevelopment of car aerodynamics it is obvious that there is still a\nstrong demand on verification and validation of schemes and models\ninvolved in the numerical codes. This is reflected by the\nconstantly high number of publications dealing with the matter. One\nof the test cases most often adopted for the purpose is the generic\ncar model proposed by Ahmed et al. This is because of its\ngeometrical simplicity and the realistic complex flow field which\nis reproducibly generated in its wake and makes it a selective test\ncase. Another reason is the availability of comprehensive\nexperimental data sets, amongst others the one we reported in an\nearlier paper. The velocity data covers the complete flow field\naround the model but focuses on the wake region. Besides mean\nvalues it provides turbulence quantities such as Reynolds stresses\nand other higher-order statistical moments measured using\nlaser-doppler anemometry (LDA).<\/div><div class=\"htmlview paragraph\">After reviewing the results of numerous CFD approaches and\ncomparing those to the experimental data it turns out that most\ndeficiencies arise from the failing prediction of detachment and\nreattachment of the flow on the rear body at a slant angle of 25\u00b0.\nA closer analysis reveals a severe underestimation of the\nfluctuating quantities in the wake and most notably in the shear\nlayers between the outer flow and the recirculation region. This\nfact in turn can be directly associated with the difficulties in\npredicting reattachment. Because of these findings further LDA\nmeasurements with high spectral resolution were performed at\nselected locations. One major aim of the study was to identify the\ntime scales of the fluctuations and in this way to come to\nsuggestions what measures are advisable to reduce the uncertainties\nboth in CFD and experimental results.<\/div><\/div><\/jats:p>","DOI":"10.4271\/2012-01-0592","type":"proceedings-article","created":{"date-parts":[[2012,4,13]],"date-time":"2012-04-13T09:21:25Z","timestamp":1334308885000},"source":"Crossref","is-referenced-by-count":4,"title":["Spectral Density and Time Scales of Velocity Fluctuations in the Wake of a Simplified Car Model"],"prefix":"10.4271","volume":"1","author":[{"given":"Hermann","family":"Lienhart","sequence":"first","affiliation":[{"name":"Univ. of Erlangen"}]},{"given":"Jo\u00e3o Pedro","family":"P\u00eago","sequence":"additional","affiliation":[{"name":"Fac. Engenharia - Univ. Porto"}]}],"member":"2796","published-online":{"date-parts":[[2012,4,16]]},"reference":[{"key":"ref0","doi-asserted-by":"crossref","unstructured":"Ahmed, S. Ramm, G. Faltin, G. \u201cSome Salient Features of the Time-Averaged Ground Vehicle Wake,\u201d SAE Technical Paper 840300 1984 10.4271\/840300","DOI":"10.4271\/840300"},{"key":"ref1","doi-asserted-by":"crossref","unstructured":"Lienhart, H. Becker, S. \u201cFlow and Turbulence Structure in the Wake of a Simplified Car Model,\u201d SAE Technical Paper 2003-01-0656 2003 10.4271\/2003-01-0656","DOI":"10.4271\/2003-01-0656"},{"key":"ref2","unstructured":"ERCOFTAC \u201cERCOFTAC \u2018Classic Collection\u2019 Database\u201d http:\/\/cfd.mace.manchester.ac.uk\/ercoftac\/index.html Sep. 2011"},{"key":"ref3","doi-asserted-by":"crossref","unstructured":"Menter, F.R. Kuntz, M. \u201cAdaptation of Eddy-Viscosity Turbulence Models to Unsteady Separated Flow Behind Vehicles\u201d, in \u201cThe Aerodynamics of Heavy Vehicles: Trucks, Buses, and Trains\u201d Lecture Notes in Applied and Computational Mechanics 19 McCallen, Rose Browand, Fred Ross, James 2004 3-540-22088-7","DOI":"10.1007\/978-3-540-44419-0_30"},{"key":"ref4","unstructured":"Bendat, J.S. Piersol, A.G. \u201cRandom Data Analysis And Measurement Procedures\u201d John Wiley & Sons New York 978-0471040002 1986"},{"key":"ref5","unstructured":"Nobach, H. \u201cKERN\u201d http:\/\/ldvproc.nambis.de\/programs\/kern.html Sep. 2011"},{"key":"ref6","doi-asserted-by":"crossref","unstructured":"Nobach, H. \u201cLocal time estimation for the slotted correlation function of randomly sampled LDA data\u201d Experiments in Fluids 32 2002 337 345 10.1007\/s003480100362","DOI":"10.1007\/s003480100362"},{"key":"ref7","doi-asserted-by":"crossref","unstructured":"Bearman, P.W. Near wake flows behind two- and three-dimensional bluff bodies Journal of Wind Engineering and Industrial Aerodynamics 69-71 1997 33-54 0167-6105 10.1016\/S0167-6105(97)00146-3","DOI":"10.1016\/S0167-6105(97)00146-3"}],"event":{"name":"SAE 2012 World Congress & Exhibition","start":{"date-parts":[[2012,4,24]]},"number":"192355","location":"Detroit, Michigan, United States","acronym":"ANNUAL"},"container-title":["SAE Technical Paper Series"],"original-title":[],"link":[{"URL":"https:\/\/saemobilus.sae.org\/downloads\/papers\/2012-01-0592\/Full%20Text%20PDF","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T11:10:27Z","timestamp":1760008227000},"score":1,"resource":{"primary":{"URL":"https:\/\/saemobilus.sae.org\/papers\/spectral-density-time-scales-velocity-fluctuations-wake-a-simplified-car-model-2012-01-0592"}},"subtitle":[],"proceedings-subject":"SAE Technical Paper Series","short-title":[],"issued":{"date-parts":[[2012,4,16]]},"references-count":8,"URL":"https:\/\/doi.org\/10.4271\/2012-01-0592","relation":{},"ISSN":["0148-7191","2688-3627"],"issn-type":[{"type":"print","value":"0148-7191"},{"type":"electronic","value":"2688-3627"}],"subject":[],"published":{"date-parts":[[2012,4,16]]},"article-number":"2012-01-0592"}}