汽车工程、核工程、水下工程、航空、轨道交通等领域中普遍存在与流动有关的多物理场耦合问题，研究流场与力、热等其它物理场之间的关联对理解气动力形成机理、流动传热、流动控制等具有重要意义。然而，风洞实验里一直缺乏完整的多物理场耦合测量手段，各种测量设备之间难以协调控制，导致多物理量之间的关联性数据获取困难。本文基于物联网概念，采用外部控制和数据截获方式，控制PIV、热线、热电偶、测力天平等单项风洞实验技术协调工作，实现多物理场耦合测量，并研发了控制系统及软件，利用该技术研究了贴壁二维方柱绕流与壁面摩擦应力关联机制、汽车发动机舱流动与传热关联机理。论文主要研究结果如下：（1）研发了风洞多物理场耦合测量技术，开发了控制系统及软件，可进行流场、压力、气动力、温度场、结构振动等多个矢量场、标量场的协同测试，获取时空关联数据。系统采用大量的自动控制设计，可提升PIV测试速度50倍以上，并降低人为因素引入的不确定度。研发了汽车整车风洞多物理场测试系统，通过截获汽车测力天平的信号数据，增加热线、麦克风、压力耙等测试设备，完成整车气动力与特征流场之间的相关性研究，测试系统已得到了工程界的认可。（2）研究了贴壁二维方柱绕流与壁面摩擦应力之间的关联。研发了壁面动态摩擦应力测量技术，解决热线近壁定位困难的难题，突破了传统热线在测量摩擦应力时方向不敏感的局限。研究发现，流动经过贴壁二维方柱会产生两类典型涡结构：逐渐向壁面靠近并与壁面接触的近壁涡，本文称为I涡；沿流向运动且与壁面保持一定间距的远壁涡，本文称为II涡。两类涡的出现均会使当地壁面摩擦应力的均方根值增大，且可能改变瞬态摩擦应力方向。I涡与摩擦应力测点上游壁面接触时，会在下游诱导下扫流动，使测点瞬时摩擦应力发生陡增；II涡从摩擦应力测点壁面上方经过时，会在壁面附近诱导局部回流，使测点瞬时摩擦应力锐减。（3）研究了汽车发动机舱等效模型流动与传热关联问题。在发动机部件上方与侧壁交界处、发动机下方与变速箱交界处存在由螺旋形高温气流滞留引起的局部高温。通过加装小风扇、导流板等流动控制措施，削弱了螺旋形气流运动，引导低温流体进入高温区，实现局部冷却。

Multi-physical field coupling problems that related to flow generally exist in automobile engineering, nuclear engineering, underwater engineering, aviation, rail transit, etc. It is of great significance to study the relationship between flow field and other physical fields such as force and heat, which could help understand the mechanism of aerodynamics, flow heat transfer, flow control, etc. However, effective multi-physics coupling measurement methods in wind tunnel experiments are lack. Multiple measurement techniques are difficult to coordinate and control, resulting in difficulties in obtaining correlation data between different physical quantities.Based on the concept of the Internet of Things, external control and data capture techniques were used to control measurement systems in wind tunnel experiments, such as PIV, hot wire, thermocouple, and force-measuring balance, in order to realize multi-physical field coupling measurement. The controlling system and software were developed, which were applied in two research works: the correlation mechanism between the wake of a 2D wall-mounted cylinder and the wall shear stress; the correlation mechanism between the flow and heat transfer in a car engine compartment. The main findings in the thesis are listed as follows:(1) The system and software of the wind tunnel multi-physical field coupling technology were developed, which could carry out joint measurement of multiple vector fields and scalar fields such as flow, pressure, aerodynamic force, temperature, structural vibration, etc., and obtain correlation data in spatial and temporal. The system uses a large number of automatic control methods, which can improve the efficiency of PIV system by more than 50 times, and reduce the uncertainty introduced by human factors. Based on this technique, a multi-physics field measurement system used for the vehicle wind tunnel was developed. By capturing the signal of the vehicle force balance, flow measurement systems such as hot wire, microphone and pressure tapes were added. The correlation between the vehicle aerodynamic force and the characteristic of flow field is able to be studied using this technique. The system has obtained approval in engineering.(2) The correlation between the wake of a wall-mounted cylinder and the wall friction was studied. A dynamic shear stress measurement technology has been developed, which solves the difficulty of locating problems of hot wire near the wall, and breaks through limitations of the insensitivity to the shear stress direction in traditional single hot wire. The results indicate that there are two types of characteristic vortex structure behind the wall-mounted cylinder. One type of the vortex, which moves towards the wall after vortex splitting and finally contacts with the wall, is named as type I vortex; the other type of the vortex, which moves along the flow direction and keeps a certain distance from the wall, is named as type II vortex. When type I vortex contacts with the wall, the instantaneous wall shear stress downstream will increase sharply, and the direction of the shear stress could be changed from the back-flow direction to the free-stream direction; when type II vortex passes over the wall, the instantaneous shear stress on the local wall will decrease sharply, and the direction the shear stress could be changed from the free-stream direction to the back-flow direction.(3) The correlation between the flow and heat in a car engine compartment was studied. The results show that the temperature distribution in the engine compartment is non-uniform. Two local high temperature regions exist in the windward side of the engine. One locates at at the junction between the upper part of the engine and the side wall, and the other locates at the junction between the lower part of the engine and the gearbox. The high temperature in these two regions is caused by the heat accumulation attribute to the spiral air flow. Effective flow control methods including adding small fans and deflectors were carried out to weaken the spiral airflow movement, or lead the low-temperature fluid into the high-temperature zone, in order to achieve local cooling.