文章提出了流水槽区域采用结构加强类产品(composite body solution,CBS)支架方法,将流水槽区域由于刚度不足引起的车内轰鸣噪声和行人保护成人头部得分进行平衡,既可降低车内轰鸣噪声,又能改善行人保护头部得分。将CBS支架材料基本参...文章提出了流水槽区域采用结构加强类产品(composite body solution,CBS)支架方法,将流水槽区域由于刚度不足引起的车内轰鸣噪声和行人保护成人头部得分进行平衡,既可降低车内轰鸣噪声,又能改善行人保护头部得分。将CBS支架材料基本参数、力学特性曲线与常见金属材料对比,得到CBS骨架材料具有低杨氏模量、低屈服强度特性;并根据材料应力应变力学特性曲线,识别出行人保护成人头部得分对材料线性段和非线性段敏感度,得到力学特性曲线屈服段对头部伤害更高的结论。基于三档全油门加速工况车内轰鸣噪声主要噪声传递函数(noise transfer function,NTF)贡献路径,采用拓扑优化方法得到初始CBS支架轮廓结构,根据模具成型需求将轮廓具体结构细化。对具体的CBS结构分别进行噪声和行人保护验证,结果显示:右悬置Z向激励到车内驾驶员外耳处响应噪声水平相比基础状态在70~80 Hz频段改善2 dB,在150~170 Hz频段改善约3 dB,行人保护相比基础状态得分提高1分,达到了噪声和行人保护平衡的目的,验证了此方法应用于解决车内轰鸣噪声和行人保护得分冲突的可行性,为后续车型开发中遇到此类问题提供了解决方案。展开更多
Computations and Experiments were performed to get an understanding of the flow field around a rectangular supersonic air intake with pointed cowl [90°] at different back pressures for Mach 2.2. The effect of Cow...Computations and Experiments were performed to get an understanding of the flow field around a rectangular supersonic air intake with pointed cowl [90°] at different back pressures for Mach 2.2. The effect of Cowl shape on the ramp surface pressure distribution is discussed and compared with existing V-Notch [90°] intake model at free exit condition. It was found that using pointed cowl [90°] intake model, a better pressure recovery was achieved compared to the V-Notch [90°] intake model at Mach 2.2. Both Pointed and V-Notch intake models showed good starting characteristics. For change in back pressure, the occurence of normal shock, flow separation zone and flow reversal were observed. All experiments are performed only for the Pointed cowl [90°] intake model. All the 3-D computations were performed by using software available at B.I.T, Mesra, Ranchi.展开更多
The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic inlets.Many studies on inhibiting the sep-aration and managing the strength of the ...The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic inlets.Many studies on inhibiting the sep-aration and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been conducted.However,the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little investigated.Therefore,the interaction of the cowl shock wave and boundary layer under thefluence of the expansion waves is studied by inviscid and viscous numerical simulations.The results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave,and that there are four types of inter-action processes with the change of the relative impingement positions of cowl shock wave.The expansion waves have a different influence on the shock wave and boundary layer inter-action at different incident points.When the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder,the influence of expansion waves is weakened,and the magnitude of separation zone increases.However,when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder,the separation can be effectively controlled.In particular,while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder,the separation is best inhibited.Compared with the upstream and downstream inci-dent points,the scale of separation area in the optimal control region is reduced by 65.3%at most.Furthermore,the total pressure recovery coefficientfirst increases and then decreases when the cowl moves from upstream to downstream,and the total pressure recovery coefficient reaches the maximum value of 68.36%at the incident position of cowl shock wave d Z 8.09d0.ª2024 The Authors.Publishing services by Elsevier B.V.on behalf of KeAi Communications Co.Ltd.展开更多
文摘文章提出了流水槽区域采用结构加强类产品(composite body solution,CBS)支架方法,将流水槽区域由于刚度不足引起的车内轰鸣噪声和行人保护成人头部得分进行平衡,既可降低车内轰鸣噪声,又能改善行人保护头部得分。将CBS支架材料基本参数、力学特性曲线与常见金属材料对比,得到CBS骨架材料具有低杨氏模量、低屈服强度特性;并根据材料应力应变力学特性曲线,识别出行人保护成人头部得分对材料线性段和非线性段敏感度,得到力学特性曲线屈服段对头部伤害更高的结论。基于三档全油门加速工况车内轰鸣噪声主要噪声传递函数(noise transfer function,NTF)贡献路径,采用拓扑优化方法得到初始CBS支架轮廓结构,根据模具成型需求将轮廓具体结构细化。对具体的CBS结构分别进行噪声和行人保护验证,结果显示:右悬置Z向激励到车内驾驶员外耳处响应噪声水平相比基础状态在70~80 Hz频段改善2 dB,在150~170 Hz频段改善约3 dB,行人保护相比基础状态得分提高1分,达到了噪声和行人保护平衡的目的,验证了此方法应用于解决车内轰鸣噪声和行人保护得分冲突的可行性,为后续车型开发中遇到此类问题提供了解决方案。
文摘Computations and Experiments were performed to get an understanding of the flow field around a rectangular supersonic air intake with pointed cowl [90°] at different back pressures for Mach 2.2. The effect of Cowl shape on the ramp surface pressure distribution is discussed and compared with existing V-Notch [90°] intake model at free exit condition. It was found that using pointed cowl [90°] intake model, a better pressure recovery was achieved compared to the V-Notch [90°] intake model at Mach 2.2. Both Pointed and V-Notch intake models showed good starting characteristics. For change in back pressure, the occurence of normal shock, flow separation zone and flow reversal were observed. All experiments are performed only for the Pointed cowl [90°] intake model. All the 3-D computations were performed by using software available at B.I.T, Mesra, Ranchi.
基金supported by the Project 1912,the National Natural Science Foundation of China (Grant Nos.52125603 and 11972139)the Fundamental Research Funds for the Central Universities (HIT.BRET.2021006 and FRFCU5710094620).
文摘The interaction of cowl shock wave and boundary layer has a crucial effect on the stability,operability and performance of hypersonic inlets.Many studies on inhibiting the sep-aration and managing the strength of the interaction of the shock wave and boundary layer with expansion corner have been conducted.However,the expansion waves near the circular arc shoulder to effectively control the interaction and cowl shock arrangement is little investigated.Therefore,the interaction of the cowl shock wave and boundary layer under thefluence of the expansion waves is studied by inviscid and viscous numerical simulations.The results reveal that the expansion waves have an important impact on the interaction between the cowl shock wave and boundary layer and the strength of shock wave,and that there are four types of inter-action processes with the change of the relative impingement positions of cowl shock wave.The expansion waves have a different influence on the shock wave and boundary layer inter-action at different incident points.When the incident point of the cowl shock wave goes far downstream from the end of the circular arc shoulder,the influence of expansion waves is weakened,and the magnitude of separation zone increases.However,when the expansion waves are applied to the interaction of the cowl shock wave and boundary layer on the circular arc shoulder,the separation can be effectively controlled.In particular,while the expansion waves interact with the shock wave and boundary layer in the back half of the circular arc shoulder,the separation is best inhibited.Compared with the upstream and downstream inci-dent points,the scale of separation area in the optimal control region is reduced by 65.3%at most.Furthermore,the total pressure recovery coefficientfirst increases and then decreases when the cowl moves from upstream to downstream,and the total pressure recovery coefficient reaches the maximum value of 68.36%at the incident position of cowl shock wave d Z 8.09d0.ª2024 The Authors.Publishing services by Elsevier B.V.on behalf of KeAi Communications Co.Ltd.
