| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Wind tunnel investigation on two-types of Circulation Control Wing are carried out, and numerical simulation is made. The basic airfoil NASA GA(W)-1 is modified at the trailing edge part. The first model has fixed circular trailing edge with two jet slots arranged in tandem, the model is also used as one-jet model, and the second one is one-jet model which has semi-circular Coanda flap, which is retractable rotationally to form the cruising congiguration. Experimental conditions are as follows : wind velocity is 10m/s, and the Reynolds number based on the chord length is 2.7X10^5. For two-jet model, jet strength is expressed as jet power coefficient C<pai> instead of jet momentum coefficient C<mu> Effective attack angle is determined by the Kind's method. Lift and pitching moment are determined by pressure integral around the airfoil and drag is by wake traverse. The following results are obtained. As to high lift characteristis, dual jet is superior to the singleone for the negative attack angle and C_<lmax>=4.6 is obtained for C<pai>=0.8,<alpha>=-4゜, whereas in the case of one jet C_<lmax>=4.6 for C<pai>=1.0,<alpha>=0゜. This means two-jet system is more efficient. Incidentally C<mu>=0.18 for both cases. In the range of zero or positive attack angle and for strong jet,the second jet blocks the flow along the lower surface, which modifies the effective airfoil shape and this causes flow separation on the upper surface, resulting in lift drop. The same characteristics is observed for one jet case. As to the second model, Coanda flap is effective giving C_1=4.8 for C)=0.2and <alpha>=6゜. Considering the results on both models, higher lift well be obtained by the use of Thwaites type small flap attached at round trailing edge.
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