We apply the adhesion approximation to study the formation and evolution of voids in the Universe. Our simulations – carried out using 128 particles in a cubical box with side 128 Mpc – indicate that the void spectrum evolves with time and that the mean void size in the standard COBE-normalised Cold Dark Matter (hereafter CDM) model with h50 = 1, scales approximately as D̄(z) = D̄0 √ 1+z , where ...

The pressure variations associated with a filling undulating pipeline containing an entrapped air pocket are investigated both experimentally and numerically. The influence of entrapped air on abnormal transient pressures is often ambiguous because the compressibility of the air pocket permits the liquid flow to accelerate but also partly cushions the system, with the balance of these tendencie...

We present a theoretical study of void spins and their correlation properties. The concept of the spin angular momentum for an unbound void is introduced to quantify the effect of the tidal field on the distribution of matter that make up the void. Both the analytical and numerical approaches are used for our study. Analytically, we adopt the linear tidal torque model to evaluate the void spin-...

THE FRACTURE of ductile solids has frequently been observed to result from the large growth and coalescence of microscopic voids, a process enhanced by the superposition of hydrostatic tensile stresses on a plastic deformation field. The ductile growth of voids is treated here as a problem in continuum plasticity. First, a variational principle is established to characterize the flow field in a...

Open volumes with partial surface geometry are often encountered in the industry while modifying or morphing legacy meshes or while creating meshes in structural recesses or void regions. The paper describes an algorithm for auto-generating hexahedral meshes on these open volumes without the need for laborious CAD repairs. Based on the available input, the open volumes are first topologically c...

In the context of a continuing investigation of factors that affect the sensitivities of energetic materials to detonation initiation, we have carried out a molecular dynamics characterization of void defects in crystalline (1,3,5-trinitro-1,3,5-triazacyclo-hexane). An empirical force field that is capable of handling flexible molecules in a pliable crystal was used. Voids ranging in size from ...

The size distribution of the mini-filaments in voids has been derived from the Millennium Run halo catalogs at redshifts z = 0, 0.5, 1 and 2. It is assumed that the primordial tidal field originated anisotropy in the distribution of the void halos which resulted in the presence of the mini-filaments in the void regions ad that the mini-filaments in the voids are pristine without being modified ...

This paper addresses the void fraction of polydisperse particles with a Weibull (or Rosin-Rammler) size distribution. It is demonstrated that the governing parameters of this distribution can be uniquely related to those of the lognormal distribution. Hence, an existing closed-form expression that predicts the void fraction of particles with a lognormal size distribution can be transformed into...