声速

For example, when passing at low altitude supersonic aircraft, when the head and tail of the aircraft will have the pressure and density of mutations through the surface formed after the N-shaped shock wave reflection, reached the ground sounds like explosions, this special sound of noise is called the H -.

例如，当超声速飞机在低空掠过时，在飞机头部和尾部会产生压力和密度突变，经地面反射后形成N形冲击波，传到地面时听起来像爆炸声，这种特殊的噪声叫做轰声。

The delivery of high-speed jet is equivalent to several times the speed of sound, so jet pump can easily handle large capacity in a vacuum and the material.

其输送的高速喷射相当于声速的几倍，因此喷射泵也能够轻而易举地在真空中处理大容量的物质。

It turns out that the flow and noise characteristics are quite complex and different from those of incompressible jets due to existence of quasi-periodic shock cell structures.

超声速射流是一般工业和军事工业中得到广泛应用的重要流动现象，对其流动特性和声学特性的研究，在实际应用和学术研究上有重要的理论价值和实际意义。

The processed results show that the new bond index curve is relatively smooth and the value is close to one in the well-bonded second interface, which can basically eliminate the influence of the formation velocity on the bond quality of second interface and can improve the evaluation quality of second interface.

评价结果表明，新的胶结指数曲线在固井Ⅱ界面胶结良好井段相对较平滑且数值接近于1，基本能够消除地层声速对Ⅱ界面胶结质量的影响，进而改进了固井Ⅱ界面的评价质量。

Two different velocity potential functions corresponding respectively to the liquid above and below the damping spacer are assumed.

研究表明：在相同密度分布条件下，可压缩流体的界面扰动增长速率总是比相应的不可压缩流体的界面增长率大，其相对增长率D随扰动波长的增加而增大，也随两种介质的声速减少而增大，在长波和易压缩流体中，D值可达0.8以上。

It can be seen from this article that the two methods have demonstrated the working capacity for calculation of frictional force and thermal load on surface of a hypersonic winged flight vehicle, which moves in dense atmospheric layers on a trajactory with stationary values of velocity head.

由文可见，对于在稠密大气层内，沿轨道运行头速度恒定的高超声速有翼飞行器，能够用本文所采用的两种方法计算其表面摩阻和热载荷。

Results show that the performance of this VCRT basically reaches the original objective,which indicates that a convergent-divergent blade passage in the high pressure rotor and a convergent-divergent meridian plane of the VCRT are suitable for the VCRT.

结果表明，对转涡轮各方面性能基本达到了设计目标，说明高压动叶采用收扩型叶栅通道且整个涡轮子午流道也采用收扩结构的设计可以获得满意性能；三排叶片仍有改进余地，即涡轮效率还有进一步提升的潜力；高压动叶出口沿整个叶高均为超声速，出口马赫数节距平均值在1.4~1.6之间；高压动叶尾缘斜激波强度以中展为中心向两侧递减；涡轮性能随出口背压的增加而下降；涡轮出口背压的变化对高压转子性能基本没有影响，但对低压转子性能的影响较大。

Mach two equals twice the speed of sound.

二马赫相当于声速的二倍。

The W-shaped tailless aircraft has not stabilizer and vertical tail,and it is based on the design of forward-swept wing and the integrated design of blended wing-fuselage.

W型无尾飞机基于前掠翼及翼身融合的一体化设计，取消了平尾和垂尾，可大幅降低雷达反射截面积，减轻结构重量；同时具有亚声速气动效率高、横航向操纵面效率高的优势。

The study shows that regenerative cooling can meet the airframe/engine integrated cooling requirements in the range of flight Mach numbers from 6 to 12, as fuel injection concept (injector locations and injection fuel mass flow) is set properly, and hydrogen temperature at the exit of cooling passage is allowed to be a relative higher value.

研究表明，在马赫数6～12的范围内，通过适当配置燃料喷射方案和提高冷却通道出口冷却剂的温度，采用再生冷却方式能够满足机体／发动机一体化高超声速飞行器的冷却需求。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。