Tham khảo tài liệu 'wind tunnels and experimental fluid dynamics research part 18', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 668 Wind Tunnels and Experimental Fluid Dynamics Research Lengthwise pressure centre coefficient is shown in figure 11. Fig. 11. Lengthwise pressure centre coefficient Front axial force coefficient is shown in figure 12. Fig. 12. Front axial force coefficient CFD results There are four kinds of grid. The first step is to value which kind of grid is more suitable for this dome CFD simulation. The drag comparison table is shown in table 2. Compared with the wind tunnel experiments result the structire grid is more suitable for this kind of simulation. Then using the structure grid more CFD simulations have been done. And we can get the precision of CFD simulation. The comparison table is shown in table 3. Wind Tunnel Experiments for Supersonic Optical-electrical Seeker s Dome Design 669 Speed Ma 2 Structure grid Un-structure grid Mix grid Polyhedra grid Table 2. Drag comparison table CFD Wind tunnel error 4 Drag 5 Lift 6 Pressure centre 1306 1418 6 Drag 13 Lift Pressure centre 1362 1448 6 8 Drag Lift Pressure centre 1526 1457 4 Drag 17 Lift 6 Pressure centre 1561 1408 10 0 Drag 14 Lift -43 0 - Pressure centre 1182 1294 9 2Ma 2 Drag Lift 15 Pressure centre 1528 1434 5 Drag Lift Pressure centre 1497 1462 3Ma 10 Drag Lift Pressure centre 1529 1471 Table 3. CFD and wind tunnel experiments comparison table The biggest error is the drag value at Mach attack angle 4 and the best CFD simulation is the lift value at Mach 3 attack angle 10 . The average drag error is the average lift value is and
