Search

Lift coefficients, C L , of single bubbles in linear shear flows are measured to investigate effects of the bubble shape, the liquid velocity gradient and the fluid property on C L . The range of the Morton number, M , tested is from log M = − 6.6 to − 3.2. The shapes of bubbles are spherical and ellipsoidal. A correlation of bubble aspect ratio for single bubbles in infinite stagnant liquids proposed in our previous study can give good evaluations for bubbles in the linear shear flows. The C L of spherical bubbles at low bubble Reynolds numbers, Re , depend on the dimensionless shear rate Sr and Re and decrease with increasing Re . These characteristics agree with the Legendre-Magnaudet correlation. The use of a single dimensionless group such as Re , the Eötvös number, the Weber number and the Capillary number cannot correlate C L of non-spherical bubbles. The trend of the critical Re for the reversal of the sign of C L is the same as that for the onset of oscillation of bubble motion, which supports the mechanism proposed by Adoua et al., at least within the range of −6.6 ≤ log M ≤ −3.2. An experimental database of C L is provided for validation of available C L models and CFD. [ABSTRACT FROM AUTHOR]

Aspect ratios E of ellipsoidal bubbles in infinite stagnant clean liquids are measured for log M = −6.6, −5.5, −4.9 and −3.9, where M is the Morton number. An empirical correlation of E applicable to a wide range of the Morton number is proposed by making use of the present data and Sugihara's data at log M = −11 (2007). The aspect ratio in this correlation is expressed in terms of the combination of the Eötvös number and the bubble Reynolds number to account for the effects of the inertial, viscous, buoyant and surface tension forces on E . Terminal velocities of ellipsoidal bubbles are accurately predicted by using the proposed correlation and a drag correlation proposed by Rastello et al. (2011). [ABSTRACT FROM AUTHOR]

The cluster components in the ground-state structure of He-isotopes are analysed through a new AMD approach. The method is called AMD triple-S which has been developed on the basis of the anti-symmetrized molecular dynamics (AMD), the generator coordinate method (GCM) and the stochastic variational method (SVM). In the AMD triple-S, variational calculations are carried out by means of the GCM with the AMD wave functions produced by the SVM procedure. [Copyright &y& Elsevier]