Flow-induced noise is a common problem in practical engineering. The classical acoustic analogy model is insufficient to evaluate the characteristic distribution of the acoustic field using only acoustic pressure as a reference. Proceeding from a four-dimensional linear wave equation with sound pressure and sound velocity vectors as variables. by choosing the Kirchhoff surfaces to enc... https://ashleyshomestores.shop/product-category/8-piece-sectional-with-chaise-and-audio-system/