压差阻力

双层集装箱列车过隧道空气压差阻力实验研究

Experimental research on pressure drag of the double container car passing through tunnel

超空泡减阻机理的研究表明：超空泡不仅可以减小回转体的摩擦阻力，还可以减小回转体的压差阻力。

Research on drag reduction mechanism of supercavitation shows that supercavitation can reduce not only the friction drag coefficient but also the pressure drag coefficient .

后体越扁平，其压差阻力系数越大；

The more the afterbody flatness , the more the pressure drag .

这表明压差阻力对振动的扰动强弱取决于边界层分离的程度。

This establishes that disturbance of pressure drag depends on the degree of boundary layer separation .

物体在水中运动受到的阻力分为三种：摩擦阻力、压差阻力和兴波阻力。

The drag form is divided into threetypes : friction , pressure drag and wave resistance .

边界层分离的程度越大，引起的压差阻力也就越大。

The greater is the degree of boundary layer separation , the higher is the pressure drag .

实验验证了过大的压差阻力将使测试泵的性能急剧下降，振动剧烈。

It is proved that a higher pressure drag will rapidly lower the performance of testing pump and cause acute vibration .

实验证明：所开发的气泡致动器可以有效地进行延迟分离，降低压差阻力，实现了主动流动控制。

The experiment results demonstrate that the balloon actuators can be used for separation delay and drag reduction to realize active flow control .

关于增阻的原因主要有：一方面坡面薄层水流的绕流作用，在床面突起物后形成尾涡，造成压差阻力，另一方面与自由表面失稳后形成的附加阻力有关。

One reason for the increased resistance is the pressure difference resistance caused by trailing vortex of obstacles under the detouring action of surface shallow flow .

但由于凹环对气流的扰动增加了激波阻力，故包含底部阻力及激波阻力的压差阻力减小并不显著，仅为0.4%。

However , the rings only reduce the pressure drag by 0.4 % because the rings disturb the external flow and increase the shock wave drag .

得到空泡闭合位置对压差阻力系数、摩擦阻力系数、总阻力系数的影响。

The influence of the location of the cavity closure on the pressure drag coefficient , friction drag coefficient and the total drag coefficien are analyzed .

结果显示，由于矩形形貌的影响，形成了压差阻力，压差阻力随形貌突起高度或密度的增加而增大，随突起占空比的增加而减小。

The difference between the front and back bulge edges results in pressure drag which increases with increasing bulge density and height , and with decreasing duty ratio .

计算了车头车尾的压差阻力，分析了列车克服阻力高速运行时的热积聚现象，得到了系统的经济运行参数。

The pressure drag between headstock and tailstock is calculated as well . Heat accumulation phenomenon is analyzed when the train moves at high speed by overcoming resistance .

分析了非光滑表面对车身外流场的影响情况，以及对车身压差阻力和摩擦阻力的影响。

On the basis of test data , the paper analyzed the impact of non-smooth surface on flow field , and the effect on pressure drag and friction resistance .

由于前缘涡的影响，翼型厚度增加，平均压差阻力系数变小，甚至会出现负值。

As airfoil thickness is increased , the average pressure drag , affected by leading edge vortex is reduced even to be negative , and meanwhile friction has little increase .

同时，系统相关参数的波动是不可避免的，能够控制的是边界层分离程度，用其减弱压差阻力的波动强度，降低水力振动。

The fluctuation caused by relative system parameters is inevitable , but the degree of boundary layer can be controlled to weaken vibration strength from pressure drag and lower hydro vibration .

船舶或水下航行器移动时，一般会遇到三种阻力：兴波阻力、压差阻力和摩擦阻力（摩擦阻力来自航行器和周围水流之间的相互阻力）。

When ships or underwater crafts move , there are three kinds of resistances which are wave making resistance , pressure resistance and tangential resistance ( tangential resistance comes from the resistance between craft and the surrounding water ) .

主动控制边界层法利用导流滚子给边界层注入动量，以推迟边界层的分离，使尾涡区变窄，从而减小厢式货车的压差阻力；

The active boundary layer control method uses the baffle roller to inject the momentum for boundary layer to delay the separation of boundary layer , narrow the wake vortex area and reduce the pressure resistance of van type vehicles .

结果表明压差阻力是推进阻力的主要组成部分，在90°攻角划水时五指并拢具有更高推进效率。

The results show that the forces caused by pressure difference are the major part of the propulsive forces , swimming with fingers holding together provides higher propulsive efficiency than swimming with fingers splaying when the angle of attack is 90 ° .

基于流体的边界层理论，从理论上分析和阐述了压差阻力波动对离心泵振动的影响，并通过对比实验对其进行了验正。

On the basis of fluid theory of boundary layer , as an instance , practical pump is used to analyze and illustrate the influence of pressure drag fluctuation on centrifugal pump vibration in theory and it is proved by contrast test .

介绍热管空气预热器更换以后使用情况，分析热管热效率、积灰结垢、腐蚀、密封泄漏、热管压差阻力及经济效益

This paper presents the running conditions of our plant after replacing the heat pipe preheater , analyzes the heat efficiency of heat pipe , sediment incrustation , corrosion , seal leakage , pressure drag of heat pipe , as well as the economic profit

测试车处于列车前部、机后第三节车时，平均空气压差阻力比明线空气阻力大80%~95%。

When the tested double container car locates in the third car behind the locomotive , the mean pressure drag of the double container passing the tunnel is much greater than that of running on open air , and the increase values are 80 % ~ 95 % .

用全压差法测通风阻力的精度研究

Research on the Precision of Ventilating Resistance Measured by the Method of Total Pressure Difference