Orlev Scientific Computing, Ltd.

Other

Ormat Industries Ltd.

Eugene Levich

Lawrence Sirovich

Lucien Y Bronicki

Sture Karlsson

Turbulence is controlled in boundary layer or wall-bounded fluid flow fields having a turbulent wall region which under natural conditions, has an average system of roll pairs or streaks adjacent the surface, and extending in the direction of flow, by locally introducing into the turbulent wall region, by passive means, a disturbance that enhances or inhibits the roll pairs thereby locally increasing or decreasing the turbulence in the flow field.

Apparatus for controlling turbulence in boundary layer and other

Turbulence is controlled in boundary layer or wall-bounded fluid flow fields having a turbulent wall region characterized by a system of roll pairs extending in the direction of flow, and obliquely propagating structures interacting with the system of roll pairs, by locally introducing into the turbulent wall region two separate disturbances that are effective to produce, in a local region, a composite disturbance field that is strongly coupled to and modifies the obliquely propagating structures in a manner that increases or decreases the interaction of the propagating structures with the system of roll pairs thereby locally increasing or decreasing the turbulence in the flow field. One of the disturbances may result from the interaction of the fluid with a linear strip, or an array of strips, of delta-shaped protrusions positioned spanwise on the wall (i.e., transverse to the flow direction); and the second disturbance may result from injecting sonic energy into the local region. Furthermore, a linear strip or an array of airfoil shaped protrusions can be used for producing a pair of counter rotating rolls for controlling turbulence in the boundary layer.

Method and apparatus for controlling turbulence in boundary layer and

Turbulence in a wall-bounded fluid flow field having a turbulent wall region characterized by a system of roll pairs extending in the direction of flow, and propagating structures interacting with the system of roll pairs, is controlled by introducing into the turbulent flow, a disturbance that changes the character of the propagating structures directed at an inclined angle to the direction of flow. Where the disturbance increases the amplitudes of the propagating structure, turbulent mixing or heating is increased; and when the disturbance decreases the amplitude of the propagating structure, the turbulent drag is decreased.

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Tel Aviv, Israel

Eugene Levich