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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The relations connecting perturbations in acoustic and entropy modes in a gasaffected by a constant mass force, are derived. The background temperature of agas may vary in the direction of an external mass force. The relations areindependent on time. They make possible to decompose the total vector ofperturbations into acoustic and non-acoustic parts uniquely at any instant.%The conclusions of distribution of the energy between sound and entropy modesmay be also made at any instant. In order to do this, three quantities arerequired, according to the number of modes. In one dimension, the referencequantities may be total perturbations in entropy, pressure and velocity. Thetotal energy of flow is determined. The examples of dismemberment of the totalfield into acoustic and entropy parts relate to the unperturbed temperature ofa gas which linearly depends on the spacial co-ordinate.

Proper orthogonal decomposition of eigen modes in a gas affected by a mass force