New stochastic models have been developed to simulate atmospheric ice accretions at low values of impaction parameters. In 2-dimensional models of ice accretion on cylindrical objects (disks impinging on a larger size disk) the restriction of rectilinear trajectories is removed and some flow dynamics is introduced by analytically calculating the droplet impact direction, in relationship to the aerodynamic conditions. Moreover, polydisperse droplets are considered instead of monodisperse ones. The numerical experiments indicate that the growth direction of the rime feathers can be theoretically predicted by a simple relationship involving three characteristic growth angles. Comparisons with experimental and theoretical results are presented. Model simulations in 3-dimensions (monodispersed spheres impinging on a particle embryo or a cylinder) have been obtained with a purely ballistic approach (rectilinear trajectories). The 3-D density has also been computed, by integrating along the axis of the cylinder circular sectors of 1 degree in width. Comparison with a 2-D density profile confirms the angle β=20° as the main growth characteristic for 3-D aggregates.

Stochastic models of ice accretion

PRODI, Franco;PORCU', Federico
1994

Abstract

New stochastic models have been developed to simulate atmospheric ice accretions at low values of impaction parameters. In 2-dimensional models of ice accretion on cylindrical objects (disks impinging on a larger size disk) the restriction of rectilinear trajectories is removed and some flow dynamics is introduced by analytically calculating the droplet impact direction, in relationship to the aerodynamic conditions. Moreover, polydisperse droplets are considered instead of monodisperse ones. The numerical experiments indicate that the growth direction of the rime feathers can be theoretically predicted by a simple relationship involving three characteristic growth angles. Comparisons with experimental and theoretical results are presented. Model simulations in 3-dimensions (monodispersed spheres impinging on a particle embryo or a cylinder) have been obtained with a purely ballistic approach (rectilinear trajectories). The 3-D density has also been computed, by integrating along the axis of the cylinder circular sectors of 1 degree in width. Comparison with a 2-D density profile confirms the angle β=20° as the main growth characteristic for 3-D aggregates.
1994
Prodi, Franco; Smargiassi, E.; Porcu', Federico
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/462621
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 1
social impact