Helicity Spectra and Dissipation

Both dissipation of helicity and it spectrum we are study on the basis of asymptotic model. Introduction into model dependence of angle between turbulent components vorticity and velocity on the governing parameters leads to the spectra of helicity observed experimentally and obtained by DNS model computations by various authors. At the same time, it settles the problem of helicity dissipation divergence with growing Reynolds number

Particle Lifting Processes in Dust Devils

Particle lifting in dust devils on both Earth and Mars has been studied from many different perspectives, including how dust devils could influence the dust cycles of both planets. Here we review our current understanding of particle entrainment by dust devils by examining results from field observations on Earth and Mars, laboratory experiments (at terrestrial ambient and Mars-analog conditions), and analytical modeling. By combining insights obtained from these three methodologies, we provide a detailed overview on interactions between particle lifting processes due to mechanical, thermal, electrodynamical and pressure effects, and how these processes apply to dust devils on Earth and Mars. Experiments and observations have shown dust devils to be effective lifters of dust given the proper conditions on Earth and Mars. However, dust devil studies have yet to determine the individual roles of each of the component processes acting at any given time in dust devils