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

. Information of aerodynamic parameters of volcanic ash particles, such asterminal velocity, axis ratio, and canting angle, are necessary forquantitative ash-fall estimations with weather radar. In this study,free-fall experiments of volcanic ash particles were accomplished using atwo-dimensional video disdrometer under controlled conditions. Samples containing a rotating symmetric axis were selected and divided intofive types according to shape and orientation: oblate spheroid withhorizontal rotating axis (OH), oblate spheroid with vertical axis (OV),prolate spheroid with horizontal rotating axis (PH), prolate spheroid withvertical rotating axis (PV), and sphere (Sp). The horizontally (OH and PH)and vertically (OV and PV) oriented particles were present in proportions of76 % and 22 %, and oblate and prolate spheroids were in proportions of76 % and 24 %, respectively. The most common shape type was OH (57 %). The terminal velocities of OH, OV, PH, PV, and Sp were obtained analyzing2-D video disdrometer data. The terminal velocities of PV were highest compared to those ofother particle types. The lowest terminal velocities were found in OHparticles. It is interesting that the terminal velocities for OH decreasedrapidly in the range 0.5 D 1  mm, corresponding to thedecrease in axis ratio (i.e., smaller the particle, the flatter the shape).The axis ratios of all particle types except Sp were found to be convergedto 0.94 at D>2  mm. The histogram of canting angles followed unimodal and bimodal distributionswith respect to horizontally and vertically oriented particles,respectively. The mean values and the standard deviation of entire particleshape types were close to 0 and 10 ∘ , respectively,under calm atmospheric conditions.

Free-fall experiments of volcanic ash particles using a 2-D video disdrometer