Cut-on, cut-off transition of sound in slowly varying flow ducts
نویسنده
چکیده
The cut-on/cut-off transition of a slowly varying acoustic mode in a slowly varying hard-walled duct with irrotational isentropic mean flow is studied. The usual turning point behaviour was found.
منابع مشابه
Sound propagation in slowly varying lined flow ducts of arbitrary cross section
Sound transmission through ducts of constant cross section with a uniform inviscid mean flow and a constant acoustic lining (impedance wall) is classically described by a modal expansion, where the modes are eigenfunctions of the corresponding Laplace eigenvalue problem along a duct cross section. A natural extension for ducts with cross section and wall impedance that are varying slowly (compa...
متن کاملExperimental investigation on sound of a centrifugal blower and fluctuating pressure on its volute
The Research has shown that the primary sound source in centrifugal turbomachines is the blade passing frequency noise, which is caused by due to impac rotor exit flow with the volute and the wild pressure fluctuations. In this paper, a centrifugal blower with forward facing blades has been selected and the sound created by it in the output channel has been investigated in different operating c...
متن کاملThe effects of cut-off walls on repulsing saltwater based on modeling of density-driven groundwater flow and salt transport
Abstract: A two-dimensional fully implicit finite difference model, which can be easily extended to three dimensions, is developed to study the effect of cut-off walls on saltwater intrusion into the aquifers. This model consists of a coupled system of two nonlinear partial differential equations which describe unsteady density-driven groundwater flow and solute transport. The numerica...
متن کاملThe effect of price changes on optimum cut-off grade of different open-pit mines
Maximizing economic earnings is the most common goal in cut-off grade optimization of open-pit mining operations. When this is the case, the price of the product has a critical effect on optimum value of cut-off grade. This paper investigates the relationship between optimum cut-off grade and price to maximize total cash flow and net percent value (NPV) of operation. In order to visualize this ...
متن کاملNumerical study on the acoustic field of a centrifugal fan and the tonal noise sources
The widespread use of squirrel cage fans, especially in ventilation and home and industrial environments, has led to the formation of many research efforts to improve performance and reduce the sound produced by this type of fan. In the literature, the most important factor in generating sound in this category of fans is the confrontation between the rotor exit flow and the volute of the fan. I...
متن کامل