Fourier–Bessel theory on flow acoustics in inviscid shear pipeline fluid flow

• A new wave equation is mathematically formulated based on potential theory.
• A new solution based on Fourier–Bessel theory is proposed.
• Calculation procedure of axial wave number is given.
• Wave propagation in laminar and turbulent flow is numerically analyzed.

Flow acoustics in pipeline is of considerable interest in both industrial application and scientific research. While well-known analytical solutions exist for stationary and uniform mean flow, only numerical solutions exist for shear mean flow. Based on potential theory, a general mathematical formulation of flow acoustics in inviscid fluid with shear mean flow is deduced, resulting in a set of two second-order differential equations. According to Fourier–Bessel theory which is orthogonal and complete in Lebesgue Space, a solution is proposed to transform the differential equations to linear homogeneous algebraic equations. Consequently, the axial wave number is numerically calculated due to the existence condition of non-trivial solution to homogeneous linear algebraic equations, leading to the vanishment of the corresponding determinant. Based on the proposed method, wave propagation in laminar and turbulent flow is numerically analyzed.