Blow-off Ball Course Presentation

  Vortex is a type of alternating rotation direction of air flow vortex. This air flow vortex has some correlation with the vortex structure formed in the interior of superfluids. The former only requires a common temperature environment, while the latter requires extremely low temperatures. Laboratory uses liquid mercury to create extremely low temperatures to form a superconducting state. In this extreme case, the flow of electrons suddenly becomes unimpeded, which is called superfluidity. The Karman vortex is Fluid MechanicsThe phenomenon of Karman vortices is important in nature and is often encountered. When a steady, uniform flow of fluid around certain objects is subjected to certain conditions, periodic vortices with opposite rotation directions and regular arrangements are shed from both sides of the object. After undergoing nonlinear interactions, these vortices form Karman vortices. Examples include the flow of water over bridge piers, the wind blowing over tall towers.ChimneyWires and other objects can form Karman vortex streets. Karman vortex streets have some very important applications, so it is necessary to understand their research history and related application situations.

 Vortex Destruction: If the alternating shedding frequency of vortex streets coincides with the acoustic standing wave frequency of an object, resonance can occur. In industry, preheaters, BoilerThe structure is mainly composed of circular pipes. When the fluid flows around the circular pipe, the alternating shedding of Karman vortex streets can cause the vibration of the air column in the preheater box. If the alternating shedding frequency of the vortex streets coincides with the acoustic standing wave frequency of the object, acoustic resonance will occur, causing the tube box to vibrate violently. In serious cases, the tube box may be dislocated or even broken. If the inherent frequency of the tube box and the gas is changed to be out of phase with the shedding frequency of the Karman vortex streets to avoid resonance, the destruction of the equipment can be prevented.