5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan rag and Lift Predict

Transcription

1 5th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 45 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan rag and Lift Estimation from 3- Velocit Field ata Measured b Multi-Plane Stereo PIV Hirouki Kato Kisa Matsushima Makoto Ueno Shunsuke Koike Shigea Watanabe Jaan Aerosace Exloration Agenc Chofu, Toko 8-85 Jaan kato.hirouki@jaxa.j Abstract For airlane design, it is crucial to hae tools that can accuratel redict airlane drag and lift. Usuall drag and lift rediction methods are force measurement using ind tunnel balance. Unfortunatel, balance data do not roide information contribution of airlane to comonents to drag and lift for more recise and cometitie airlane design. To obtain such information, a ake integration method for use drag and lift estimation as deeloed for use in ake sure data analsis. Wake sure data is commonl measured b multi-hole ressure robes. But ressure robe measurement requires considerable time, so that it is difficult to al man conditions in ind tunnel testing. On the other hand, PIV measurement ossesses the abilit to acquire elocit distribution data at relatiel short times. Hoeer, PIV measurement does not roide ressure data directl. Therefore, the ressure estimation technique is deeloed to enhance the alue of PIV data. The technique conducts comutational fluid dnamics (CF) comutation to estimate ressure field using multi-lane stereo PIV elocit data. Finall, drag and lift rofiles are redicted b the ake integration method using elocit data measured b PIV and ressure data estimated b CF. Ke ords: Wind Tunnel Testing, Flo Measurements, Wake, PIV Introduction In general, the aerodnamic forces exerted on a ind tunnel test model are obtained using an aerodnamic force balance, hich measures the integrals of ressure and friction on the model s surface and gies a near-field reresentation of the aerodnamic forces. Wake integration method is an attractie tool both for ind tunnel testing and CF analsis, mainl because it can render the sanise distribution of drag and lift isible quantitatiel, and this knoledge of the aerodnamic force distribution is useful for drag source identification. Additionall, it can decomose drag into induced drag and rofile drag comonents. rag decomosition gies insight into the flo hsics necessar for design imroement. But ressure robe measurement requires considerable time, so that it is difficult to al man conditions in ind tunnel testing. On the other hand, PIV measurement ossesses the abilit to acquire elocit distribution data at relatiel short times. Hoeer, PIV measurement does not roide ressure data directl. Therefore, the ressure estimation technique is deeloed to enhance the alue of PIV data. The technique conducts comutational fluid dnamics (CF) comutation to estimate ressure field using PIV elocit data. Finall, drag and lift rofiles are redicted b the ake integration method using elocit data measured b PIV and ressure data estimated b CF. In the erification rocedures, this technique ere erformed of the PIV data of the NACA00 rectangle ing model in ind tunnel testing, and the drag and lift forces estimated b PIV data directl comared ith measured balance data. This document is roided b JAXA.

2 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan rag and Lift Prediction Method The Poisson equation for ressure (equation ()) is the basic equation for the comutation. The equation is deried fro the diergence form of three-dimensional incomressible Naier-Stokes equations. It is assumed that elocit gradient in the freestream direction is 0 and a flo is stead. Then the to dimensional equation is obtained. All terms of the equation are discretied using the nd-oder central difference method. General coordinates transformation is done for ide alicabilit of the sstem. The discretied Poisson equation for ressure hich is a simultaneous linear equation sstem is soled numericall b SOR (successie-oerrelaxation) method []. Re () The aerodnamic forces are exressed as the balance of momentum oer a control olume around the model. Although the classical far-field method requires the integration of hsical roerties oer the entire surface of the control olume, Bet succeeded in confining the integral to the inside the model s ake for to-dimensional ind tunnel drag measurement, and the theor as extended to three-dimensional ind tunnel testing b Maskell. Maskell s method as eoch-making as it required lanar traersing measurement onl ithin the ake of a ind tunnel model to acquire aerodnamic drag and lift forces (Figure ). Figure Image of ake integral control olume. The ake integral method is described b Kusunose[] in detail. The drag coefficient (C) is ritten as C = CP+CI+CP+O (3) () CP, CI, CP are rofile drag coefficient, induced drag coefficient, nd order rofile drag coefficient, resectiel. And rofile drag coefficient (CP) is as follos S U dd R s P CP (3) Re () C = CP+CI+CP+O (3) () S U dd R s P CP (3) JAXA Secial Publication JAXA-SP-3-00E 46 This document is roided b JAXA.

3 5th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 47 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan enominator in right-hand side is dnamic ressure, and S control olume surface area. P,, U are static ressure, densit, elocit of freestream, resectiel, and s is erturbation entro, R is gas constant. is integral area oer the model ake region. Induced drag (CI) is as follos dd dd (4) (4) CI CI U S U S is x-comonent of orticit ector, and, to-dimensional stream function, and are as follos,, (5) (5) nd order rofile drag is as follos P s dd R CP P s dd (6) R (6) U S CP U S Lift coefficient is as follos U CL u P dd U M ds M sds (7) R U U US U Wind Tunnel Testing A conentional lo-seed ind tunnel ith a m x m test section as used for the resent PIV test. A hotograh of the ind tunnel model is shon in figure. The model is a NACA00 rectangular ing (chord = 00 mm, san =,000 mm). The test as conducted at a freestream elocit U of 30.0m/s. Angle of attack () as set in a range beteen 0º and 8º. Figure The ind tunnel test model of NACA00 rectangle ing. 3 This document is roided b JAXA.

4 48 JAXA Secial Publication JAXA-SP-3-00E 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan A stereoscoic (3-C) PIV sstem hich has been deeloed for the JAXA ind tunnels as emloed for the resent test. In the PIV measurement, the laser light sheet as located erendicular to the freestream (figure 3). Figure 3 Schematic of Stereo PIV setting. A stereoscoic (3-C) PIV sstem hich has been deeloed for the JAXA ind tunnels [3] as emloed for the resent test. In this measurement, stereoscoic PIV ith to cameras ith different ie angles ere erformed. Figure 3 shos stereoscoic PIV configuration. In some cases, e emloed to measure three comonents of elocit. In ector rocessing, e alied seeral stes of elocit ector alidation. After the alidation, ensemble instantaneous data at an identical test condition are aeraged. Oil drolets ith a diameter of around m ere used as the seed articles. In the stereoscoic PIV measurement, the sheet as located erendicular to the free stream. Interrogation sot sie is 3 x 3 ixels ith 50% oerla. Time searation t as set from 45 to 55 s ste b 0. s in order to reduce bias error due to difference of t. Figure 4 Laser light sheet otics. Exerimental Results Figure 5 shos three comonents of elocit distribution measured in the ind-tunnel testing. Color contour shos a elocit comonent of the freestream direction (u). 4 This document is roided b JAXA.

5 5th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 49 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan Figure 5 multi-lane stereo PIV results (U=30m/s, AoA=8deg). Figure 6 shos ressure distributions estimated from three elocit comonents b CF method. In the case of attack of angle 8 degree, it is qualitatiel good results that there are lo ressure region near a ing ti ortex. Figure 6 multi-lane stereo PIV results (U=30m/s, AoA=8deg). Figure 7 and 8 sho rofile drag distribution (cd) and induced drag distribution (cdi), resectiel. These results are calculated from three elocit comonents and ressure distribution at ake region b ake integration method. The comutational code deeloed and alidated b Ueno et. al[4] as used alied ake integration method. Figure 7 multi-lane stereo PIV results (U=30m/s, AoA=8deg). 5 This document is roided b JAXA.

6 430 JAXA Secial Publication JAXA-SP-3-00E 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan Figure 8 multi-lane stereo PIV results (U=30m/s, AoA=8deg). In the rofile drag distribution, there are large drag comonents at the model and model suorts. On the other hand, in the induced drag distribution, thre are eaks of rofile drag near the ti ortex at attack of angle 8 degree. Figure 9, 0 and sho rofile drag, induced drag and lift distributions in sanise direction, resectiel. Also in the sanise distributions, rofile and induced drag denote the same tendenc of the distributions in the ake lane. In the lift distribution, it is fairl good results that there is a eak at center of the ing san. Figure 9 multi-lane stereo PIV results (U=30m/s, AoA=8deg). Figure0 multi-lane stereo PIV results (U=30m/s, AoA=8deg). Figure multi-lane stereo PIV results (U=30m/s, AoA=8deg). 6 This document is roided b JAXA.

7 5th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 43 5 th Smosium on Integrating CF and Exeriments in Aerodnamics (Integration 0) 3-5 October 0 JAXA Chofu Aerosace Center, Toko, Jaan Conclusions Pressure distribution is estimated from three elocit comonents at ake lane measured b stereo PIV sstem b CF technique. It is deeloment that the technique is alicable to ake integration method b means of elocit distribution measured b PIV and ressure distribution estimated b CF The ind tunnel testing as carried out in order to alidate this technique. NACA00 rectangle ing model as used in the ind tunnel testing. In the result, the drag estimated b PIV data is 0.0 differences from balance data due to the model suorts. On the other hand, he lift estimated b PIV data is fairl good agreement ith balance data, hile the difference beteen PIV and balance is from 0.0 to Also, the rofile and induced drag estimation is qualitatiel good results about ake lane distributions and sanise distributions. Finall, It is demonstrated that rofile and induced drag and lift force can be estimated b onl PIV data. Acknoledgments The authors are indebted to Junichi Akatsuka and Akiko Hidaka, Wind Tunnel Technolog Center, JAXA. The authors are also indebted to the members of Lo-Seed Wind Tunnel Section, Wind Tunnel Technolog Center, JAXA for their suort to the ind tunnel exeriments and the data rocessing. References [] Kusunose, K.: A Wake Integration method for Airlane rag Prediction, Tohoku Uniersit Pres., 005. [] Aso, T., Matsushima, K. Nakahashi, K.: CF Pressure Estimation using PIV ata. Proceedings of 006 KSAS-JSASS Joint International Smosium,,59-63, 006. [3] Watanabe, S.; Kato, H.: Stereo PIV Alications to Large-Scale Lo-Seed Wind Tunnels, AIAA Paer , 003. [4] Ueno, M. Akatsuka, J. and Hidaka, A.: rag ecomosition Analsis of CF ata of the LR-F6 Model, AIAA Paer , This document is roided b JAXA.