<![CDATA[Karakteristik aliran melalui silinder berpenampang ellips selalu menarik untuk dikaji. Penambahan kekasaran permukaan pada leading egde sebuah silinder berpenampang ellips diduga mampu menunda titik separasi aliran yang melintasi silinder ellips tersebut. Penelitian dilakukan secara eksperimental di subsonic wind tunnel dengan model uji silinder tunggal berpenampang ellips. Model uji dialiri udara pada dua bilangan Reynolds 3,8.104 dan 6,8.104 dengan angle of attack 0¢X. Bentuk model uji silinder berpenampang ellips dengan rasio diametris (t/c) =: 0,333 serta penambahan kekasaran(e/c)= 4,94 x 10-4 pada leading edge. Pada model uji dipasang pressure tap setiap 50 di sepanjang kontur silinder ellips untuk mengukur distribusi tekanan yang terjadi.Dari hasil pengujian dapat diperoleh kesimpulan bahwa kenaikan bilangan Reynolds akibat kenaikan kecepatan aliran untuk model uji tanpa kekasaran menyebabkan letak titik separasi mundur ke belakang sehingga luasan wake menyempit. Untuk Re=3,8.104, penambahan kekasaran pada model uji akan menyebabkan titik separasi tertunda ke belakang dibanding bila model uji tanpa kekasaran. Untuk Re=6,8.104, penambahan kekasaran pada leading edge model uji akan menyebabkan titik separasi lebih tertunda ke belakang dibanding bila tanpa kekasaran. The flow characteristic across elliptical cylinder is still interest to be studied. This research were conducted experimentally using subsonic wind tunnel with a single elliptical cylinder experiment model. The experiment model was streamed by air at two Reynolds number 3,8.104 and 6,8.104 with angle of attack 0¢X. The ellipse model have a chord length (c) and the ratio of thickness 0.333. At the leading edge of ellipse was installed a perturbation by addition of surface roughness having relative (e/c) of about 4,94.10-4. Pressure taps were installed at the experiment model each 50 alongside contour of elliptical cylinder to measure pressure distribution that happened.The result of experiment showed that increasing of Reynolds number, due to increasing of velocity flow on smooth surface experiment model, will cause a delay of separation point, so the area wake decreased. At Reynolds number 3,8.104 addition of surface roughness at ellipse will cause the separation point delay than the smooth surface ellipse. For Reynolds number 6,8.104, the addition of surface roughness can more delay the separation point compared to the smooth surface ellipse.]]>
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