First Experience with a Fast Staring Infrared Camera System

Abstract

during a siniplc at1 hoc t,cst, in tlic TH2-sliock t,uiiiicl of RWTI-I Anclien for capt,iiriiig aiitl post-imaging of fxst siirfnce terril)erat,iire t,raiisiciit,s oii ii liy1)ersoiiic forclmly riiodcl c,oiifigiira.t,ioii (Fig. I ) . 111 order t,o image tempera.t,iirc t,raiisicnt,s on tliis 1110del iiiatlc fi-om ca,rl)oii film, 1.111: liist,ory of variaiit, infi.a,rccl snrfacr r;ttli;ition TVX capturctl tliiriiig sonic oiitls of cst,ahlishetl flow coiitlit,ions 1 2 ~ ~ niorc tJiaii 20 frniiics p(’r shot,. Prior t 8 0 t;liis test an oil-site t,wo 1)oiiit corrcctioii m t l teiril)c,rat,iire calil)ra.t,ion of t,lic camera T Y ~ S pcrformctl wvit,li a 1)lac.k botly iiist,alltd n c x tJie iiiotlcl iii t lic t,est scct;ioii of t.hc sliock tiiniicl. Infrared rni1i;Ltivc fliix (la t,a aqiiiretl fi-om t,lic s i i r fxe of tlic riiotlcl cmiiltl t h i s he t,raiisforriietl int,o siirfacc kiiiper;it,iires w1iic.h are iisctl tm calciilate the prtyxiit, acro!,lierniotl~~l;llliic. lieat fl i is tlist,ril)iit,ion oil it,s si irfx(>. T h e model itself was eqiiippcd wit,li coii-T:ciit.ioiial tlicriiiocoiiplcs iiicorporat,ec! along t,lie cent,crliiie of tlie bot1tom model wall arid tjlic esteiitletl Iiody flap. All d a t a iiieasiiretl 11y the t,lierrrioconplos arc iised for perforining corrr:l;~t,ions wit,li acqnirerl iinage (lata iiiformation. Tlie capture of image tliLtn was initialized liy a, trigger signal from a pressiire traiistliicer wliicli seiised t,lie pressure impulse of t,lie shock wavc rinining through the tiinnel after riipturc of it,s tliap1ir:qpi. The forebody rnotlel i n i1priglit8 att i tude and iiicliiictl by 20 (leg. t,o the flow vect.or was rota.t.ctl toget,lic>r witli the suspensioii system ;~l)out t h flow axis l ~ y 90 deg., so t h t tJic bot,tZorri of tlic niotlci could hc observetl by the camera througli 1111 infi.aretl wiiidow at the side of the test sectioii c l imi l~er (Fig. 2) . Unfortunately t,lie axial posit,ion of t,lie avaiiable window was fixed as was the at,titiidc of the model, so I;liai, minor iinfavoiirat,c> reflcctioiis iri a~coidai i r r wit;li tliis test set-lip ~ o n l d 11cjtj bc avoided. opc1-atrct a t , 1000 fran1cs/seco11tl :Illcl has 1)ccYl pro\-etl Uecmse cvcii 110 mirrors t o alter t,lic optical path were availalile) t,lie txxst, set,-ii1) was arccptcd as tlcscri-