Global Resolution of the Physical Vacuum Singularity for Three-Dimensional Isentropic Inviscid Flows with Damping in Spherically Symmetric Motions

2017 ◽  
Vol 226 (1) ◽  
pp. 33-82 ◽  
Author(s):  
Huihui Zeng
2007 ◽  
Vol 111 (1125) ◽  
pp. 699-704 ◽  
Author(s):  
G. Zhu ◽  
P. W. Bearman ◽  
J. M. R. Graham

AbstractThe present paper continues the work of Zhuet al. The closed-form expressions for the evaluation of forces on a body in compressible, viscous and rotational flow derived in the previous paper have been extended to different forms. The expressions require only a knowledge of the velocity field (and its derivatives) in a finite and arbitrarily chosen region enclosing the body. The equations are implemented on three-dimensional inviscid flows over wings and wing/body combinations. Further implementation on three-dimensional viscous flows over wings has also been investigated.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mengxu Liu ◽  
Biping Gong

Abstract The gravitational wave (GW) has opened a new window to the universe beyond the electromagnetic spectrum. Since 2015, dozens of GW events have been caught by the ground-based GW detectors through laser interferometry. However, all the ground-based detectors are L-shaped Michelson interferometers, with very limited directional response to GW. Here we propose a three-dimensional (3-D) laser interferometer detector in the shape of a regular triangular pyramid, which has more spherically symmetric antenna pattern. Moreover, the new configuration corresponds to much stronger constraints on parameters of GW sources, and is capable of constructing null-streams to get rid of the signal-like noise events. A 3-D detector of kilometer scale of such kind would shed new light on  the joint search of GW and electromagnetic emission.


1980 ◽  
Vol 102 (3) ◽  
pp. 728-737 ◽  
Author(s):  
D. Adler

Recent developments in inviscid prediction methods of internal flow fields of centrifugal impellers and related flows are critically reviewed. The overall picture which emerges provides the reader with a state-of-the-art perspective on the subject. Restricting simplifying assumptions of the various methods are identified to stimulate future research. Topics included in this review are: two-dimensional subsonic and transonic inviscid flows as well as three-dimensional inviscid flows.


2021 ◽  
Vol 118 (29) ◽  
pp. e2103822118
Author(s):  
Siddhansh Agarwal ◽  
Fan Kiat Chan ◽  
Bhargav Rallabandi ◽  
Mattia Gazzola ◽  
Sascha Hilgenfeldt

Modern inertial microfluidics routinely employs oscillatory flows around localized solid features or microbubbles for controlled, specific manipulation of particles, droplets, and cells. It is shown that theories of inertial effects that have been state of the art for decades miss major contributions and strongly underestimate forces on small suspended objects in a range of practically relevant conditions. An analytical approach is presented that derives a complete set of inertial forces and quantifies them in closed form as easy-to-use equations of motion, spanning the entire range from viscous to inviscid flows. The theory predicts additional attractive contributions toward oscillating boundaries, even for density-matched particles, a previously unexplained experimental observation. The accuracy of the theory is demonstrated against full-scale, three-dimensional direct numerical simulations throughout its range.


2020 ◽  
Vol 22 (3) ◽  
Author(s):  
Xin Liu ◽  
Edriss S. Titi

Abstract We establish the local and global well-posedness of strong solutions to the two- and three-dimensional anelastic equations of stratified viscous flows. In this model, the interaction of the density profile with the velocity field is taken into account, and the density background profile is permitted to have physical vacuum singularity. The existing time of the solutions is infinite in two dimensions, with general initial data, and in three dimensions with small initial data.


2016 ◽  
Vol 12 (3) ◽  
Author(s):  
Janusz Karkowski

A numerical method for finding spherically symmetric pseudobreathers of a nonlinear wave equation is presented. The algorithm, based on pseudospectral methods, is applied to find quasi-periodic solutions with force terms being continuous approximations of the signum function. The obtained pseudobreathers slowly radiate energy and decay after some (usually long) time depending on the period that characterizes (unambiguously) the initial configuration.


Sign in / Sign up

Export Citation Format

Share Document