【作者】 高旭东；

【导师】 武晓松；

【作者基本信息】 南京理工大学 ， 兵器发射理论与技术， 2002， 博士

【摘要】 本文首次完成了高速旋转弹丸侧喷三维干扰湍流流场的数值模拟，分析了弹丸侧喷流场复杂的波系结构，研究了高速旋转、攻角、底喷等因素对弹丸侧喷流场的影响规律，深入分析了旋转侧喷弹丸的空气动力学特性。 在旋转坐标系下，发展了一种含旋转源项的雷诺平均Navier-Stokes方程的三维有限体积TVD格式，时间离散采用隐式Euler方法。在非定常计算中，采用Jameson提出的双时间推进方法改进时间精度。湍流模型采用高雷诺数k-ε两方程模型。在改进传统网格生成方法的基础上，结合投影映射、分区拼接技术生成了弹丸侧喷流场单一区域三维计算网格，在侧喷流喷口边界实现了网格贴体化。 系统研究了低阻远程弹丸在小攻角状态，低跨声速、高跨声速和超声速时的非对称绕流流场，为该弹形气动力研究提供理论指导并为弹丸侧喷流研究奠定基础，结果显示低阻远程弹丸外形具有优化绕流场、减小空气阻力的特点。对分区计算技术在弹丸绕流场数值模拟中的应用也进行了尝试，计算表明分区后计算稳定性有所下降。 在无旋转、无攻角条件下完成了弹丸侧喷三维干扰湍流流场数值模拟，并完成了弹丸底喷流-侧喷流共同干扰流场的一体化计算。弹丸侧喷流与绕流的相互干扰形成了包含喷口前激波、再附激波以及沿喷流边界发展的膨胀波等复杂的波系结构，并延伸影响到弹底部流动。研究表明，侧喷流与来流马赫数之比是影响绕流场的重要因素，该值越大则侧喷干扰越强烈，矩形和椭圆形两种侧喷口形状对侧喷流场干扰波系的影响并不明显。侧喷口前绕侧喷流的激波和侧喷流对弹底部流动的引射导致了弹丸波阻和底阻系数的增大。底喷流动具有添质加能和引射两种相反作用，并能消弱侧喷流对弹丸底部流动的影响。 为研究高速旋转对侧喷流绕流场的影响，进行了高速旋转弹丸侧喷三维干扰湍流流场的数值模拟。与无旋转情况对比表明，旋转对弹丸侧喷流以及底部流动均有影响，高速旋转导致侧喷射流向旋转来流方向倾斜，并减弱其对弹底流动的引射。在高速旋转弹丸底喷流-侧喷流共同干扰流场的计算中，发现高速旋转对底喷流动的影响没有对侧喷流动的明显。 采用双时间推进法成功进行了有攻角高速旋转光弹体绕流和弹丸侧喷流两种非定常流场的数值模拟。计算表明，两种非定常流场在经过约一个旋转周期之后形成非定常周期流场。光弹体弹丸表面压力表现为周期性波动，从计算中得到的马格努斯力系数与实验值十分吻合。弹丸侧喷流场干扰波系的空间结构、弹体表面压力和各种空气动力参数均表现为稳定的周期性波动。 系统分析了旋转侧喷弹丸复杂的空气动力学特性，分析了马格努斯力系数、法向力系数、偏航力矩系数、俯仰力矩系数和压力中心等参数的产生机理和变化规律。与光弹体相比，旋转侧喷弹丸的空气动力特性不仅在形成机理上发生了本质变化，而且在数值上表现出复杂的波动形式，这些特点将对旋转侧喷弹丸空气动力研究带来直接和深远的影响。更多还原

【Abstract】 Three dimensional interaction flowfield over high-speed spinning projectile with lateral jets is numerically simulated in this dissertation firstly. Complicated shocks wave patterns is analyzed. Several factors concerned such as high-speed spinning, attack angle, base bleed and so on, are studied. The aerodynamics characteristic of spinning projectile with lateral jets is analyzed detailedly.In rotating frame of reference, the construction method of three dimensional finite volume TVD schemes is systemically analyzed, in which implicit Euler defiference is applied for time discretization. The high Reynolds number two-equation k- E turbulence model is used. The dual-time stepping method proposed by A.Jameson is applied to improve time precision for unsteady flowfield computation. The three dimensional grid for projectile with lateral jets, especially body-fitted for lateral jets exit, is generated by improved traditional methods with projection and zonal method.The flowfield over low-drag and long-range projectile with small attack angle is numerically studied from transonic to supersonic velocity. It provides basic work for aerodynamics characteristic of this projectile and for lateral jet interaction flowfield, and it shows this projectile can decrease drag. Zonal method is tried to compute flow over projectiles and results is satisfied, but computation is much slower.Without spinning or attack angle, the three dimensional interaction flowfield over projectile with lateral jets is numerically simulated successfully, and unified interaction flowfield with lateral jets and base bleed is also calculated. The flow field that results from the interaction of lateral jets injection into supersonic flow over projectile has complicated shocks wave patterns, which include regions of shocks and expand waves, and the lateral jet interaction also effects base flow of projectile. The ratio of Mach number between lateral jet and free flow induce intensity degree of jet interaction. It has no obvious difference between two interactions with two types of nozzle exit configuration, rectangle and ellipse. The shock in front of jet results in increase of shock resistance and the jet ejection causes increase of base resistance. The base bleed has two contrary action of providing energy and ejection, and it can weaken the effect of lateral jet upon base flow.The interaction flow field over high-speed spinning projectile with lateral jets is simulated secondly. Comparison with nonspinning case shows spinning changes the flow structure and base flow of projectile with lateral jets. The lateral jets are caused to inclineto the direction of rotating free flow and to weaken the effect upon base flow. Furthermore, the spinning effect upon lateral jet is much stronger than that upon base bleed.With attack angle, two types of unsteady flowfield over high-speed spinning projectile without and with lateral jets are successfully simulated respectively by dual-time stepping method. The two results of flowfield show unsteady and periodically after one period of spinning. The pressure of projectiles without lateral jets waves periodically and the Magnus force coefficient is in excellent agreement with the experiment data. In the result with lateral jets, the structure of jets, the pressure of projectile surface and the aerodynamics characteristics are all in steady periodical fluctuation.The complicated aerodynamics characteristic of spinning projectile with lateral jets and with attack angle is studied detailedly. The formation and changes are analyzed including Magnus force, normal force, yawing moment, pitching moment and pressure center. The aerodynamics characteristic of spinning projectile with lateral jets has constitutionally difference in formation from that without jet, and it waves periodically. These characteristics are very important for the study of aerodynamics of projectile with lateral jets.更多还原