The impact of the pitching motion on the structure of the vortical flow over a slender delta wing under sideslip angle

The primary purpose of this investigation is to observe the effect of the pitching motion on the vortical flow structure and bursting of leading-edge vortices over a delta wing under the sideslip angle, β using a dye visualization technique. In the current work, a delta wing with a sweep angle of Λ = 70° was oscillated in upstroke and downstroke direction to be able to discover the influence of pitching motion on the flow characteristics of the delta wing. The values of mean angles of attack were selected as α_m = 25° and α_m = 35°, and the sideslip angle was altered from β = 0 to 16°. The delta wing oscillated with the various periods of T_e = 5 s, 20 s, and 60 s, respectively. Amplitude of motion was adjusted as α_o =  ± 5°. It is found that the pitching motion of the delta wing under the sideslip angle β varies the location of the vortex bursting and vortical flow structure substantially.

     

A thermal analysis investigation of new insulator compositions based on EPDM and phenolic resin

New rocket insulator compositions have been studied by adding various types and amounts of fillers, such as graphite and asbestos fibres, Al₂O₃, MgZrO₂, Cr₂O₃, SiC, carbon powders and phenolic resin to the base EPDM gum and graphite, kevlar,E type glass fibres to the base phenolic resin in order to improve thermal and ablative efficiency. The degradation of the insulators has been investigated by thermogravimetry (TG) analysis to 900°C and DSC analysis to 500°C. Conversion curves of the insulators at different heating rates were performed and maximum degradation temperatures were found as 646 and 661°C for EPDM P and phenolic resin, respectively. The kinetic parameters for degradation have been evaluated and the lifetime of the rocket insulators has been estimated. Thermal analysis has been conducted on the insulators and the indepth temperature distribution was evaluated in order to find optimum insulation thickness.