OCR Text |
Show Figure 4 . Instan taneous, two-din1ensional I ser Rayleigh scattering nlea uren1ents of th fine scale structure of molecular mixing between two gases in a turbulent flow, in thi case propane gas inje ted into a collowin air stream. Shown at top i the ins ta II tancous n1ixtu re fraction field (,(x,f), giving the 10 al ext nt of nlixing, and at bollon1 the corresponding instantaneous alar energy dissipation rate field 'V("V(,(x,l) g iving the local molecular mixing rate . Eaeh uch data plane span fron1 the jet (ente:rline. at the right dge, to pure a ir in thc co llowing airstr am, at th left edge. Color iden tify the in tan t n eou propane cone ntrations and nlOle ular lllixing rates As in Fig . 2. all tile 1110leeular mixing is ('O(H'l'(ltraled all locally ollc -dilllCllsiollal wri 11 kl'd ' heet-Ii ke s tructu res, which have a se lf-Simi lar internal structure ane! are con ti n 1I a II y t r c t c h dan d 1'0 Ide cl by the un lerlyin,(f turbulent flow . The tructures form tl1 basis of the LIM model. \Vhich i 11 cor po r t e ~ the In d i r t1 yin to a n e \V solution Illethocl for the partial diff rClltial cqu 'ltion' (I J)E~s) fov'rning th' flo\V and (nixin O processes . This rce!lI cs the PD£s to a much ' iIllpler set of ordinalY cliff rential eqll'ltion (ODEs) \Vhi h can be olved on th till1 -evo lving surface on \Vhich the ' trll ~ ture '11' center d. IData frolll Bu 'h & Dahnl I 92. 1995./ u X.S .\1/'-1) U ]7 riA D 0 1.6 ~ 1\ ~ b "..( ~ t:' b.l .Q 3.5 0 |