Experimental investigation of a jet in a cross-flow by spontaneous Ratman scatter

Abstract

Ahsfruct The experimental itivcstigatioii of' threedimensional gas flc.rws requircs ircrn-int rrisive ant1 qua si po i n t I i k e mea s 11 remen t s. The re a re s t i I I few techniques for quanti t a t ivc nieasiirenients. which iiieei these demands. One nf them i.c spniitaiienws Rainan scattering which allnws to nicasure tlie tleiisity in wincl tunnels. I n a mixing I'low the par t i a l clenrily is measured. Vil?rational frequencies of niolecrilcs arc stimulatecl by a laser beam. The vilmtional Raman frcqriericy shift depends on the molccular species. The light intensity scattered iii Stokes lines is pmlmrtinnal to the molecular concentratinn in llie probe voluiiie. 'I'he probe volume has a diameter hetween 0. I a n d 0.3 inn1 aiicl a length between 0.6 ant1 0.8 ni i i i . 'flic (lata ratc is 100 to 1000 inenwreinents per second. The spontaneous Ramnn ccattering is tisetl. at ISI,. to investigate an irnpiiiging supers(-rnic jet issuecl from R circular nutlet into a supcrsonic cross-stream. The Mach ni in iber of the main flow in tlie wind tunnel i y 2.06. The inipinging jet ir n incthane jet a t Mach 2. l 'he experimental investigatinn inclutlex iiicthane ancl a i r partial dcnsities ineawrcnients i n (lic iiiipinging jc t inclucetl f l h v field arid wall pressure incasiirenrc~its along the model. On classical f luid dynamics assumptions, clensit ies ineasurcmenta are converted i 11 to part i B I p ressii res. 011 these ass ii in pt io 11 c; . we o 11 t a i t i lhe wall pressure field. 'These rerult$ are in good agreement with wall presslire nieasrii~cnieiits. Tlic lift and nioineirt cnefficients intlucccl hy t l i e jct intcraction are estimated hy tlie integration rrf the \v; iI l pressure f ie ld.