An assembly quality detection device and a method for a wind screen cleaning system based on streamline pattern, includes a main body of a test bench and a detection system. The main body of the test bench includes a test bench rack and a cleaning centrifugal fan; the inside of the test bench rack is provided with a cleaning space. The detection system includes a smoke generation and transmission device, a two-degree-of-freedom smoke fixed-point release mechanism, a high-speed image acquisition system and a control system. A fixed base is installed on the upper end of the outlet of the cleaning centrifugal fan, a linear moving guide rail device is installed on the fixed base, the linear moving guide rail device is equipped with a moving slider, the moving slider is installed with a rotating mechanism, the rotating mechanism output end is provided with a smoke releasing duct, the smoke releasing duct is communicated with the smoke generation and transmission device. The detection device and method can test the manufacturing and assembly quality of the cleaning system of the combine harvester by combining the characteristics of wind tunnel streamline pattern with image processing and corresponding mathematical operation.

Films, systems, and methods for measuring shear stress are described. In an embodiment, the film comprises an optically transmissive polymer matrix disposed on a substrate; and a liquid crystal dispersed in the optically transmissive polymer matrix, wherein at least a portion of the liquid crystal protrudes from or is exposed on a side of the optically transmissive polymer matrix opposite the substrate.

An imaging system and method for leakage detection uses schlieren imaging to locate and characterize a flow of pressurized gas with a refractive index different than ambient air. In particular, a schlieren imaging system includes a collimated light, a knife-edge spatial filter and a 4F telescopic imaging system is used to create an image of a device under test (DUT). The DUT is pressurized and monitored for leaks. When a leak is present and in the monitored plane of the DUT, contrast variation illustrates the presence, location and character of the leak. For example, a waterproof/leakproof mobile device may be evaluated for leakage between layers of modules, such as leaks in the housing of a waterproof electronics case. This detection can allow identification and characterization of the leak point via visual identification.

A system and method for optimizing passive control strategies of oscillatory instabilities in turbulent systems using finite-time Lyapunov exponents are disclosed. The method includes receiving data from one or more measuring devices connected to the turbulent flow system incorporating a control strategy in the flow field. One or more flow characteristics are determined from the data obtained from the measuring devices. The method involves computing critical dynamics from backward time finite-time Lyapunov exponent (FTLE) field based on the one or more flow characteristics. Next, one or more regions of critical dynamics associated with impending oscillatory instabilities in the turbulent flow system are identified. The identified region of critical dynamics is disrupted the control the onset of oscillatory instabilities in the turbulent flow system.

In an embodiment, a test section comprises at least one surface defining an at least partially enclosed space. The at least partially enclosed space defines an airflow path for air to flow. The test section also comprises a nozzle disposed in the at least partially enclosed space. The nozzle is configured to spray an agricultural spray and is positioned to emit the agricultural spray such that at least a section of the agricultural spray exhibits a non-parallel angle relative to the airflow path defined by the at least partially enclosed space. The test section further comprises at least one stimulus source positioned to illuminate at least a portion of the agricultural spray adjacent to the nozzle. Additionally, the test section comprises at least one detector positioned to image at least the portion of the agricultural spray adjacent to the nozzle.

A method of manufacturing. The method includes receiving, by a processor, image data of a first aircraft component subjected to an airflow. A plurality of tufts has been attached to the aircraft component. The method also includes classifying, by the processor, the plurality of tufts into a first set of separated tufts and a second set of attached tufts to form a classification output. The method also includes manufacturing a second aircraft component or reconfiguring the first aircraft component based on a design change to the first aircraft component that results from an aerodynamic analysis of the classification output.

In an embodiment, a test section comprises at least one surface defining an at least partially enclosed space. The at least partially enclosed space defines an airflow path for air to flow. The test section also comprises a nozzle disposed in the at least partially enclosed space. The nozzle is configured to spray an agricultural spray and is positioned to emit the agricultural spray such that at least a section of the agricultural spray exhibits a non-parallel angle relative to the airflow path defined by the at least partially enclosed space. The test section further comprises at least one stimulus source positioned to illuminate at least a portion of the agricultural spray adjacent to the nozzle. Additionally, the test section comprises at least one detector positioned to image at least the portion of the agricultural spray adjacent to the nozzle.

A method for analyzing fluid around a rotating body includes: a step (S100) in which a spatial model having a rotating computational mesh cell group A and a stationary computational mesh cell group B is acquired; a step (S101) in which a storage computational mesh cell group C is established; a step (S102) in which arithmetic operations for fluid analysis are performed; a step (S103) in which the physical quantity at the computational mesh cell making up the rotating computational mesh cell group A calculated as a result of arithmetic operations for fluid analysis is copied to a corresponding computational mesh cell at the storage computational mesh cell group C; and a step (S104) in which averages over time are calculated for the physical quantities at the storage computational mesh cell group C and the stationary computational mesh cell group B.

A system reproduces aerodynamic boundary layer transition conditions in a wind tunnel test environment under ambient to cryogenic temperature conditions. The system includes a test component disposed in the test environment that defines an exterior surface. A trip dot is mounted on the test component and has a first state, in which a distal surface of the trip dot is at a first elevation relative to the exterior surface of the test component, and a second state, in which the distal surface of the trip dot is at a second elevation relative to the exterior surface of the test component. An actuator is operably coupled to the trip dot and configured to transition the trip dot between first and second states. A controller remotely causes the actuator to transition the trip dot between the first and second states.

A tracer particle spreading device for a boundary layer flow visualization experiment based on a flat plate includes a tracer particle generator, a smoke storage box, and a wall-surface particle distribution box. Fume and oil are pressurized by a micro pump and flows into a heating pipe to be heated and vaporized, and then is ejected from a nozzle to form tracer particles. The tracer particles enter the smoke storage box via a smoke guiding tube. An axial flow fan is mounted on a wall surface of the smoke storage box. The tracer particles enter a cavity of the wall-surface particle distribution box via the smoke guiding tube, and the tracer particles are rectified by a rectifying plate and ejected from a spreading slit. An outlet of the spreading slit is at an angle of 15? with respect to an experiment flat plate.