An apparatus is provided for providing simulated smoke. The apparatus comprises a reservoir including a reservoir port, and a bladder disposed in the reservoir. The bladder can be deflated to cause a fluid substance to flow through the reservoir port into the reservoir to fill the reservoir with the fluid substance to generate smoke. The bladder can be inflated to cause smoke to flow out of the reservoir through the reservoir port to provide simulated smoke.

A method for testing water droplet shedding ability of a surface of an aircraft wing includes: blowing air toward a surface of a cylindrical member in an airflow direction perpendicular to an axial direction of the cylindrical member, the cylindrical member simulating the wing and having water-related surface characteristics that differ across a predetermined boundary position in a circumferential direction; supplying a water droplet to a portion of the surface of the cylindrical member on a leading edge side with respect to a flow of the air; and capturing an image of the water droplet that moves on the surface of the cylindrical member across the boundary position due to the flow of the air.

A device for testing a flow field state within a high-speed train bogie cabin; the periphery of a bogie consists of apron plates and end plates; the test device comprises: a plurality of test points evenly distributed on the inner walls of the apron plates and end plates, a plurality of image pickup devices installed in the bogie cabin, a smoke generator communicating with an inner cavity of the bogie via pipes, and one or more smoke exits provided on top of the bogie; each test point is connected to a test tape, and the distance between the test points is more than twice the test tape length. The test device monitors and records in real time the air flow direction at the end plates and apron plates by means of viewing of a fluorescent test tape. Also provided is a method of testing a flow field state within a high-speed train bogie cabin.

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.

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.

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.

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 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.

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.