The Effects of Discontinuous Boundary Conditions on the Directivity of Sound From a Piston

Time- and frequency-domain computations of broadband noise due to interaction between incident turbulence and rectilinear cascade of flat plates

“…To prevent the contamination of the unphysical wave reflected from the inflow and outflow boundaries to the internal computational domain, the perfectly matched layer (PML) method [33] is implemented as a non-reflecting boundary condition. Numerical spurious short waves are known to be generated in discontinuous boundaries [34], such as the leading and trailing edges of the blades, in the computational domain. Therefore, the artificial selective damping terms [31] are applied to the discretized equations so that the spurious waves are effectively removed.…”

“…The spanwise wavenumber k 3 is determined by assigning the spanwise vortical mode number q¼ 1 and 2 of the single harmonic gust in Eq. (34). The magnitude of the gust w 0 /W is set to be 0.01.…”

Development of Efficient and Accurate Parallel Computation Algorithm Using Moving Overset Grids on Background Multi-Domains for Complex Two-Phase Flows

“…However, as the oscillation frequency increases, there are closer agreements between the numerical and the experimental results. To ensure the property of the current numerical scheme and preserve the dispersion relation, which is an important parameter for determining the ability of this numerical scheme to simulate wave-type phenomena, the numerical wave number of the present scheme needs to be analyzed [51][52][53][54][55][56]. The critical wavenumber can be defined as |Im(k numer.c )∆x − k exact ∆x| = 0.005, according to which the critical wavenumber of the present scheme is Im(k numer.c )∆x = π/5.…”