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Complex acoustic intensity

  1. Dec 7, 2014 #1
    Hello All,

    I would like to know why do we multiply the complex conjugate of velocity (not just the velocity) with the complex pressure to obtain the complex acoustic intensity. Could someone please help me with this?

  2. jcsd
  3. Dec 8, 2014 #2
    I guess for the same reason the apparent electrical power in complex form is given by S = VI*. Correct phase angle between voltage phasor V=V⋅ev and current phasor I=I⋅ei is φ=φvi. Without conjugate you would get in the product φ=φvi. Conjugate of the current I*=Ie-jφi solves this problem since S=VI*=V⋅ev⋅I⋅e-jφi=V⋅I⋅ej(φvi).
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