英语翻译Fluid mechanics deals with the flow of fluids.It has bee

英语翻译
Fluid mechanics deals with the flow of fluids.It has been conducted
both mathematically and experimentally.Prantl posited
that there is a thin layer near the surface of the body due to frictional
effects in a viscous fluid and the rest of the flow can be considered
inviscid.The idea led to a rational way of simplifying the
equations of motion in the different regions of the flow field
[1,2].Recent efforts have concentrated on turbulent flow.Many
predictions about initiation and the subsequent history of instability
growth are based on the application of buoyancy-drag models.
These predictions often illustrate general features,the details of
which are usually traced in numerical simulations.The buoyancy-
drag models provide representations of the early time instability
growth and material penetration phases in direct comparison
with the experimental evidence in their more refined and carefully
applied versions.Transport equations describing the evolution of
both spatial and temporal scales are required to achieve accurate
descriptions of turbulent transport [3,4].At the present time,there
exists no unified turbulent model.While numerous techniques
have been proposed for identifying organization in fluid motion,
they are typically statistical rather than physical and do not necessarily
provide desirable properties.
The aim of this paper is to propose a new concept,wave surface
of boundary layer.It is the interface between the main flow and the
boundary layer.It is generated by a tiny density difference whichresults from velocity difference between the main flow and the
boundary layer in the flow.When fluid moves,wave elements will
be generated on the surface of the boundary layer.The size of a
wave element is so small that it is impossible to conduct experiments
to observe it directly.We designed a series of ‘‘enlarged
size” experiments to show the oscillatory behaviors of wave elements.
These are the long-term combined precipitation and particulate
fouling (P&PF) tests in cooling tower systems [5,6].

流体力学研究的是液体流动.这种研究已在数学和实验方面进行过.普兰特尔断定由于在粘性流体中的摩擦效果,物体表面形成一个薄层,流体的其余部分可以被认为是非粘性的.这个想法的结果是简化不同区域流场[1,2]运动方程出现一个合理方法.近期工作都集中在湍流方面.许多关于不稳定性增长起因和后果的预测都是基于浮力阻力模型的应用.这些预测往往只说明一般特点,其详细情况通常要追溯到数值模拟.这个浮力——阻力模型显示了早期时间的不稳定性增长以及与他们更精致和小心应用的实验证据进行直接比较后的材料渗透相位.从而获得描述时间和空间尺度演变的运输方程,以准确描述湍流的输送[3,4].目前,还没有统一的湍流模型.尽管在识别流体运动的组织形式方面已经提出了众多技术方法,但这些方法通常是统计性的而不是物理性,不一定能提供所需的属性.
本论文的目的是提出一个新概念,边界层的波动表面.这是主要流场和边界层之间的接触面.它是由流体主要流场和边界层之间速度差造成的微小密度差生成的.当流体移动时,就会在边界层表面生成波元素.波元素体积太小,不可能通过实验直接观察到它.我们设计了一系列的“放大体积的”实验来显示波元素的振荡行为.
这些都是在冷却塔系统[5,6]进行的长期联合降水和微粒污染(P&PF)测试.