초록 ▼

A method of detecting the onset of turbulence in connection with a body moving through a fluid medium and reducing turbulence noise in acoustic sensor systems carried thereby. First, the body is supplied with sensors each for generating a signal suitable for measuring amplitude of pressure fluctuati

A method of detecting the onset of turbulence in connection with a body moving through a fluid medium and reducing turbulence noise in acoustic sensor systems carried thereby. First, the body is supplied with sensors each for generating a signal suitable for measuring amplitude of pressure fluctuations of the medium proximate a region of said sidewall of the body in at least a region of the body in which turbulence is expected to occur. During a reference stage during which the body moves through the fluid medium when it is known that turbulence is occurring around at least a portion of said body, the sensors each generate reference temporal pressure data representing fluctuations in pressure of the fluid medium around said body. In response to reference temporal pressure data generated by sensors in a turbulence zone at which turbulence is occurring and sensors in a transition zone between the turbulence zone and a laminar flow zone, method-of-delay phase portraits are generated for a progression of selected delay intervals. During an operational stage, the signals from the sensors are filtered to generate a portion representing the turbulence due to motion of the body through the medium and a portion representing signals from external acoustic signal sources, and the turbulence signal portion is used to generate signals of appropriate phase which are injected into the medium to reduce the turbulence noise signals.

대표청구항 ▼

A method of suppressing noise induced in a fluid medium by a body moving therethrough comprising the steps of: supplying in the sidewall of the body, in at least a region of the body in which turbulence is expected to occur, sensors each for generating a signal suitable for measuring amplitude of pr

A method of suppressing noise induced in a fluid medium by a body moving therethrough comprising the steps of: supplying in the sidewall of the body, in at least a region of the body in which turbulence is expected to occur, sensors each for generating a signal suitable for measuring amplitude of pressure fluctuations of the medium proximate a region of said sidewall; during a reference stage during which the body moves through the fluid medium when it is known that turbulence is occurring around at least a portion of said body, (i) enabling the sensors to each generate reference temporal pressure data representing fluctuations in pressure of the fluid medium around said body, and (ii) generating, in response to reference temporal pressure data generated by sensors in a turbulence zone at which turbulence is occurring and sensors in a transition zone between the turbulence zone and a laminar flow zone, indicia identifying the presence of turbulence; and during an operational stage during which the body moves through the fluid medium (i) enabling the sensors to each generate operational temporal pressure data representing fluctuations in pressure of the fluid medium around said body proximate the respective sensor due to motion of the body through the medium and further due to external acoustic signal sources, (ii) detecting the onset of turbulence proximate the respective sensor in connection with such operational temporal pressure data, (iii) filtering the operational temporal pressure data to separate a portion representing an acoustic turbulence signal from the portion representing acoustic signals from external acoustic signal sources, and (iv) injecting into the medium proximate the respective sensor, in response to the acoustic turbulence signal, an acoustic signal of appropriate phase to reduce the amplitude of said acoustic turbulence signal.