Standing waves in a rectangular sound box recorded by TV holography

• A simple but informative whole-field method to visualize standing waves in air enclosures is presented. The integrated sound pressure field distribution of standing-wave patterns inside a rectangular, air-filled transparent box is measured using ordinary TV holography (also called ESPI or DSPI). The phase distribution of the sound pressure is measured by using the more complicated, phase-modulated TV holography technique. Standing waves in the box are excited by a loudspeaker. The structural vibration amplitude distribution of the walls of the same box (operational deflection shapes, ODSs) are measured at the same frequencies as the standing waves with the same optical technique. The pressure maps obtained and the corresponding structural ODSs are of great pedagogical value and can be used to verify numerical models, etc. Standing-wave patterns in non-rectangular enclosures, as the sound box of a guitar, illustrates the usefulness of the method.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Teknisk mekanik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Applied Mechanics (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)

Nyckelord

Experimentell mekanik

Experimental Mechanics

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