A phononic material and a method of using a phononic material for use in interacting with a fluid or solid flow are provided. The phononic material includes an interface surface and a subsurface feature. The interface surface is adapted to move in response to a pressure, and/or velocity gradients, associated with complex motion of a turbulent flow exhibiting a polarity of frequencies exerted on the interface surface. The subsurface feature extends from the interface surface. The subsurface feature comprises a phononic crystal or locally resonant metamaterial adapted to receive the pressure, and/or velocity gradients, from the turbulent flow via the interface surface and alter the phase and amplitude of a polarity of frequency components of the turbulent flow in order to reduce or increase the kinetic energy of the turbulent flow. The interface surface is adapted to vibrate at a polarity of frequencies, phases and amplitudes in response to the frequency, phase and amplitude of at least one component of the turbulent flow.

Low drag low noise devices are described herein that use passive jet flow control to reduce the drag and noise created by motor vehicles (e.g., motor vehicle side view mirrors and their main bodies) while the motor vehicles travel through a fluid. The low drag low noise devices described herein comprise a lengthwise axis, an outer body, and an inner body. The outer body and the inner body cooperatively define a channel through which fluid can pass during use.

A family of Radar energy Absorbing Deformable Low Drag Vortex Generators (RAD-LDVG) is described herein. This family of devices are fabricated in such a way that it can conform to aircraft surface features while reducing radar returns from structural details. Vortex generators (VGs) are typically used to reattach or smooth gross flowfields over aircraft surfaces. By doing so, an airfoil or wing can maintain attached flow at higher angles of attack and/or higher lift coefficients than one without the VGs. These devices are also used to reattach and/or smooth flows that encounter crossflow-induced instabilities and/or adverse pressure gradients on the upper surfaces of wings or near aircraft boattails. Other uses include reduction of buffet, vibration, flutter, cavity resonance or general bluff-body pressure drag reduction. Although conventional rigid VGs do generate vortical aerodynamic structures, two major problems are often experienced: i.) the inability to conform to curved surfaces, ii.) the generation of radar cross-section spikes produced by the VGs themselves.

A family of Radar energy Absorbing Deformable Low Drag Vortex Generators (RAD-LDVG) is described herein. This family of devices are fabricated in such a way that it can conform to aircraft surface features while reducing radar returns from structural details. Vortex generators (VGs) are typically used to reattach or smooth gross flowfields over aircraft surfaces. By doing so, an airfoil or wing can maintain attached flow at higher angles of attack and/or higher lift coefficients than one without the VGs. These devices are also used to reattach and/or smooth flows that encounter crossflow-induced instabilities and/or adverse pressure gradients on the upper surfaces of wings or near aircraft boattails. Other uses include reduction of buffet, vibration, flutter, cavity resonance or general bluff-body pressure drag reduction. Although conventional rigid VGs do generate vortical aerodynamic structures, two major problems are often experienced: i.) the inability to conform to curved surfaces, ii.) the generation of radar cross-section spikes produced by the VGs themselves.

Methods and related apparatus embodiments are disclosed that allow novel Conformal Vortex Generator and/or Elastomeric Vortex Generator art to improve energy efficiency and control capabilities at many surface points of a body or object moving at speed in aero/hydrodynamic Newtonian fluids, by reducing; shock energy losses, surface flow turbulence, and/or momentum layer thicknesses.

The invention relates to a flow body with a surface that has a pyramidal elevation (1) in at least one location. The elevation (1) has a rhombic base here; a first diagonal (D1) of the rhombic base is aligned in the direction of flow (S) when the flow body is in use and it has a length ratio of between 5 and 8 with respect to the second diagonal (D2).

An antenna apparatus is provided. The antenna apparatus in embodiments of this application includes a radome. An interference structure is disposed on a surface of the radome, and the interference structure is configured to change an airflow at a surface boundary layer when the airflow passes through the surface of the radome. The interference structure is disposed on the antenna apparatus to change the airflow at the surface boundary layer.

A fluid control film is provided that includes fluid control channels extending along a channel longitudinal axis. Each of the fluid control channels has a surface and is configured to allow capillary movement of liquid in the channels. The fluid control film further includes a hydrophilic surface treatment covalently bonded to at least a portion of the surface of the fluid control channels. The fluid control film exhibits a capillary rise percent recovery of at least ten percent. Typically, the hydrophilic surface treatment includes functional groups selected from a non-zwitterionic sulfonate, a non-zwitterionic carboxylate, a zwitterionic sulfonate, a zwitterionic carboxylate, a zwitterionic phosphate, a zwitterionic phosphonic acid, and/or a zwitterionic phosphonate. A process for forming a fluid control film is also provided. Further, a process for cleaning a structured surface is provided, including providing a structured surface and a hydrophilic surface treatment covalently bonded to at least a portion of the structured surface, and soiling the structured surface with a material. The process also includes removing the material by at least one of submerging the structured surface in an aqueous fluid, rinsing the structured surface with an aqueous fluid, condensing an aqueous fluid on the structure surface, or wiping the structured surface with a cleaning implement.

Systems, devices and methods are disclosed for controlling the flow of a fluid over the window of an optical instrument housing in a freestream flow field. For example, the flow upstream of the housing may be split to create a flow region over the window that is conducive to successful operation of the instrument. The flow region may be maintained for various rotations of the housing about yaw, pitch, and roll axes. The disclosed features in some embodiments induce flow regions with reduced spatial and temporal density gradients of the flow over the window.

The fluid acceleration pipe includes a main body having a pipe cavity and defining a central axis. The whole inner surface of the main body is exposed to the pipe cavity. The main body is formed with at least 3 spiral ribs arranged spacedly along a perimeter direction of the main body. A spiral groove is formed between any two adjacent ones of the spiral ribs. A column-shaped imaginary datum plane is defined by the most bottom portion of each spiral groove about the central axis. A projection of the most top portion of each spiral rib on the imaginary datum plane defines a spiral line. The lead angle of the spiral line is 50 to 60 degrees. The top portion of each spiral rib has a convex-arc-shaped surface, and the bottom portion of each spiral groove has a concave-arc-shaped surface.