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Wingtip Vortices and the Rationale of This Project Results Conclusion Wingtip vortices are the result of a pressure di#erence between the top and bottom of an a. Simulated wing tip development, bahavior and core area more closely Instantaneous Velocity over Freestream resemble that of the SPIV data for denser meshes. The physical size of vortex aircraft wing or helicopter rotor moving through air. In military applications, wing tip Velocity (U/U ) and Equivalent SPIV Images Approximate Size WPSUJDFTIBWFBEWFSTFFòFDUTPOUPXFEWFIJDMFTBOEDBVTFBEEJUJPOBMUBJMCVòFUJOH 3FG and Location of cores can thus be approximated by future simulations using a mesh size at least 4” downstream of 16” downstream of In commercial applications, winglets have been installed on passenger aircraft to minimize Simulation Vortex Cores that of Sim7. trailing edge trailing edge WPSUFYGPSNBUJPOBOESFEVDFMJGUJOEVDFEESBH 3FG 7JTVBMMZ XJOHUJQWPSUJDFTDBOCF t'VUVSFXPSLGPSUIFTJNVMBUJPOOFFENPSFBDDVSBUFMZNFBTVSFEEJNFOTJPOTBOE UIPVHIUPGBTBIPSJ[POUBMUPSOBEP BTTIPXOJO'JHVSF XIPTFDSPTTTFDUJPOBMBSFB coordinates of vortices in the 2D plane, as well as have more exact data from the SPIV increases with downstream distances. Sim0 experiments. With more accurate dimensions there is a need to numerically verify $PNQVUBUJPOBMMZ NPEFMJOHXJOHUJQWPSUJDFT UIFFSSPSPGUIFTJNVMBUJPOTJODPNQBSJTPOUP41*7EBUBUPNBLFBCFUUFSKVEHNFOU has been a challenging area of study. It has only about whether the simulations are reliable to use. been in recent years that computational tools t*GUIFTJNVMBUJPOTGPSXJOHUJQWPSUJDFTBSFSFMJBCMF UIFZDBOCFVTFEUPNBLFNPSF that better resolve and approximate wing tip Sim3 e!cient use of wind tunnel tests and aid in the design process of aircraft WPSUJDFTIBWFCFFOEFWFMPQFE5IJTQSPKFDU TPVHIUUPFYQBOEPOHBJOTCZVTJOHJODSFNFOU ally more computationally intensive simulations. Acknowledgements Determination of the accuracy of the modeled Sim7 "OBEEJUJPOBMUIBOLZPVUP3VTTFMM#JMMJOHTBU/"4"%'3$GPSIJTSPMFJONZQMBDFNFOU wing tip vortices was accomplished by BU&EXBSET"'# BOEGPSJOWFTUJOHUJNFJOUPPVSQSPGFTTJPOBMEFWFMPQNFOUBT45"3JOUFSOT comparing simulation results to experimental 5IJTNBUFSJBMJTCBTFEVQPOXPSLTVQQPSUFECZUIF4%#FDIUFM +S'PVOEBUJPOBOECZ 7JTVBM3FQSFTFOUBUJPOPG8JOHUJQ7PSUJDFT 3FG data. UIF/BUJPOBM4DJFODF'PVOEBUJPOVOEFS(SBOU/P
SPIV Any opinions, "ndings, and conclusions or recommendations expressed in this material BSFUIPTFPGUIFBVUIPSTBOEEPOPUOFDFTTBSJMZSFøFDUUIFWJFXTPGUIF4%#FDIUFM +S Part 1: Computer Simulation (Ref. 2) (Ref.2) 'PVOEBUJPOPSUIF/BUJPOBM4DJFODF'PVOEBUJPO Discussion References Numerical results of simulations sent to Instantaneous Velocity over Freestream Velocity and Equivalent SPIV Images Ref 1:"CCPUU *) WPO%PFOPò "& 5IFPSZPG8JOH4FDUJPOT*ODMVEJOHB visualization program Summary of Airfoil Data. Mineola: Dover Publications, Inc. VisIt t"MMUISFFTJNVMBUJPOTBOE41*7TIPXBDPVOUFSDMPDLXJTFiDVSMwGPSNJOHEPXOTUSFBNPGUIF right edge of the wing and from the color scale con"rms an expected inverse relationship Ref 2: *HBSBTIJ ) %VSCJO 1" .B ) )V ) "4UFSFPTDPQJD1*74UVEZPGB/FBS CFUXFFOWPSUFYWFMPDJUZBOEEJTUBODFGSPNUIFDFOUFS 3FG 'JFME8JOHUJQ7PSUFY0SMBOEP"NFSJDBO*OTUJUVUFPG"FSPOBVUJDTBOE"TUSPOBVUJDT *OD &YBNQMF%NFTIVTFEJODPNQVUFSTJNVMBUJPO t5IFTIBQFTPG4JNBOE4JNNPSFDMPTFMZSFTFNCMFUIBUPG41*7GPSCPUIEPXOTUSFBNMPDBUJPOT Ref 3:4UFXBSU 3 0DUPCFS 8BLF5VSCVMFODF$PNNFOUBSZ3FUSJFWFE+VMZ GSPN3PCZOhT'MZJOH4UBSUIUUQXXXøZJOHTUBSUDB'MJHIU5SBJOJOH145"3"TIUN Part 2: Wind Tunnel Data t4JNTIPXTNPSFEFUBJMUIBO4JNBOEJTNPTUMJLFUIF41*7QMPUT BTBUUIFwNBSLUIF QMPUDMFBSMZTIPXTBEFöOFEWPSUFYDPSFTFQBSBUFEGSPNUIFIPSJ[POUBMiXBTIwPGUIFXJOH Legends Vortex Core Size and Location Approximation U/U∞ Vortex Cores [email protected] Data from Iowa State As downstream distance from the trailing edge increases: University wind tunnel experiment compared to t4JNPOMZTIPXTJODSFBTFJOWPSUFYDPSFBSFBXJUIOPDPSFEJTQMBDFNFOU Purple = 4” downstream simulation t4JNTIPXTJODSFBTJOHDIBOHFJOBSFBBOEBDPSFEJTQMBDFNFOUVQBOEUPUIFMFGU #MVF = 8” downstream Experimental Setup using StereoScopic (SFFO wEPXOTUSFBN 1BSUJDMF*NBHF7FMPDJNFUSZ 41*7 3FG t4JNTIPXTBDIBOHFJOBSFBBOEBDPSFEJTQMBDFNFOUUIBUBQQSPYJNBUFMZGPMMPXTB 3FG 3FE wEPXOTUSFBN DPODBWFEPXOQBSBCPMJDUSBKFDUPSZGSPNSJHIUUPMFGUXIJDI XIJMFFYBHHFSBUFE resembles what is seen in the SPIV approximation.
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