Velocity-Potential Boundary-Field Integral Formulation for Sound Scattered by Moving Bodies

AIAA Journal ◽  
2018 ◽  
Vol 56 (9) ◽  
pp. 3547-3557 ◽  
Author(s):  
M. Gennaretti ◽  
G. Bernardini ◽  
C. Poggi ◽  
C. Testa
Keyword(s):  
Velocity Potential ◽  
Integral Formulation ◽  
Boundary Field ◽  
Moving Bodies ◽  
Field Integral

A nonlinear eddy-current integral formulation for moving bodies

1998 ◽  
Vol 34 (5) ◽  
pp. 2529-2534 ◽  
Author(s):  
R. Albanese ◽  
F.I. Hantila ◽  
G. Preda ◽  
G. Rubinacci
Keyword(s):  
Eddy Current ◽  
Integral Formulation ◽  
Moving Bodies

Muffler Performance Studies Using a Direct Mixed-Body Boundary Element Method and a Three-Point Method for Evaluating Transmission Loss

1996 ◽  
Vol 118 (3) ◽  
pp. 479-484 ◽  
Author(s):  
T. W. Wu ◽  
G. C. Wan
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Velocity Potential ◽  
Transmission Loss ◽  
Point Method ◽  
Integral Formulation ◽  
Pressure Jump ◽  
Direct Integral ◽  
Body Boundary ◽  
Element Method

In this paper, a single-domain boundary element method is presented for muffler analysis. This method is based on a direct mixed-body boundary integral formulation recently developed for acoustic radiation and scattering from a mix of regular and thin bodies. The main feature of the mixed-body integral formulation is that it can handle all kinds of complex internal geometries, such as thin baffles, extended inlet/outlet tubes, and perforated tubes, without using the tedious multi-domain approach. The variables used in the direct integral formulation are the velocity potential (or sound pressure) on the regular wall surfaces, and the velocity potential jump (or pressure jump) on any thin-body or perforated surfaces. The linear impedance boundary condition proposed by Sullivan and Crocker (1978) for perforated tubes is incorporated into the mixed-body integral formulation. The transmission loss is evaluated by a new method called “the three-point method.” Unlike the conventional four-pole transfer-matrix approach that requires two separate computer runs for each frequency, the three-point method can directly evaluate the transmission loss in one single boundary-element run. Numerical results are compared to existing experimental data for three different muffler configurations.

Study of Velocity-Potential Integral Formulations for Sound Scattered by Moving Bodies

AIAA Journal ◽  
2020 ◽  
pp. 1-12
Author(s):  
G. Bernardini ◽  
C. Poggi ◽  
M. Gennaretti ◽  
C. Testa
Keyword(s):  
Velocity Potential ◽  
Moving Bodies

Dynamics of comets in the collapsing protosolar nebula

1999 ◽  
Vol 173 ◽  
pp. 45-50
Author(s):  
L. Neslušan
Keyword(s):  
Solar System ◽  
Velocity Distribution ◽  
Oort Cloud ◽  
Interstellar Clouds ◽  
Protosolar Nebula ◽  
Moving Bodies

AbstractComets are created in the cool, dense regions of interstellar clouds. These macroscopic bodies take place in the collapse of protostar cloud as mechanically moving bodies in contrast to the gas and miscroscopic dust holding the laws of hydrodynamics. In the presented contribution, there is given an evidence concerning the Solar system comets: if the velocity distribution of comets before the collapse was similar to that in the Oort cloud at the present, then the comets remained at large cloud-centric distances. Hence, the comets in the solar Oort cloud represent a relict of the nebular stage of the Solar system.

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