English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Basing our discussion on the Lagrangian description of hydrodynamics, westudied the evolution of density fluctuation for nonlinear cosmologicaldynamics. Adhesion approximation (AA) is known as a phenomenological model thatdescribes the nonlinear evolution of density fluctuation rather well and thatdoes not form a caustic. In addition to this model, we have benefited fromdiscussion of the relation between artificial viscosity in AA and velocitydispersion. Moreover, we found it useful to regard whether the velocitydispersion is isotropic produces effective `pressure' or viscosity terms. Inthis paper, we analyze plane- and spherical-symmetric cases and compare AA withLagrangian models where pressure is given by a polytropic equation of state.  From our analyses, the pressure model undergoes evolution similar to that ofAA until reaching a quasi-nonlinear regime. Compared with the results of anumerical calculation, the linear approximation of the pressure model seemsrather good until a quasi-nonlinear regime develops. However, because ofoscillation arising from the Jeans instability, we could not produce a stablenonlinear structure.Comment: 12 pages, 6 figures, accepted for publication in Phys.Rev.D; some  references and sentences are correcte

Correspondence between the adhesion model and the velocity dispersion for the cosmological fluid