1030 A. Physical Oceanography OLR (1987) 34 (12)

case of linear offshore sloping bottom. The flow behavior of the estuarine plume depends on the vertical structure of flow at the river mouth, bottom slope and ambient coastal flow. Under certain conditions, a front exists as an offshore boundary of the plume. Results are compared with observations for the Changjiang River Estuary (China), and Chesapeake Bay and Savannah River estuaries. Inst. of Oceanol., Acad. Sinica, Quindao, People's Re- public of China.

Dept. of Chem. Engng, Queen's Univ., Kingston, ON, K7L 3N6, Canada.

87:6756 Griffiths, R.W. and E.J. Hopfinger, 1987. Coalescing

of geostrolflfi¢ vortices. J. Fluid Mech., 178:73-97. Res. School of Earth Sci., Australian Natl. Univ., GPO Box 4, Canberra, ACT 2601, Australia.

A300. Fluid mechanics

87:6754 Dommermuth, D.G. and D.K.P. Yue, 1987. Numer-

ical simulations of nonlinear axisymmetric flows with a free surface. J. Fluid Mech., 178:195-219.

A robust, stable numerical method is developed for nonlinear three-dimensional but axisymmetric free- surface problems using a mixed Eulerian-Lagran- gian scheme under the assumption of potential flow. Three problems are solved: (1) implementation of a far-field closure; (2) treatment of the body and free-surface intersection line; and (3) stable rep- resentation and time integration of the free surface. Computational examples are presented: the growth and collapse of a vapor cavity near the free surface; the heaving of a floating vertical cylinder starting from rest; and the heaving of an inverted vertical cone. Dept. of Ocean Engng, MIT, Cambridge, MA 02139, USA.

87:6757 Hald, O.H., 1987. Convergence of vortex methods for

Euler's equations, IH. SIAM J. appl. Math., 24(3):538-552. Dept. of Math., Univ. of Calif., Berkeley, CA 94720, USA.

8"/:6758 London, S.D., 1987. Weakly non-linear Rossby waves

in a rotating fluid of Slfl~oidal configuration. Dynam. Atmos. Oceans, 11(1):39-58.

A modified ray method is used which yields the same dispersion relation and conservation law as in the linear case, but gives an equation for a new, second order mean term. This mean term is unstable for all free oscillations on any axisymmetric bottom topog- raphy in the free surface problem. Dept. of Appl. Math. Sci., Univ. of Houston, 1 Main St., Houston, TX 77002, USA.

87:6755 Grandmaison, E.W., S. Ng and H.A. Becker, 1987. A

smoke generation system for fluid dynamics r~,~,earch. J. Phys., scient. Instrums, E, 20(1):605- 608.

A detailed description of a smoke generator system for marker nephelometry, laser velocimetry and flow visualisation research in fluid mechanics is pre- sented. In this system a low-vapour-pressure, com- mercially available oil is vaporised in a preheated chamber and the carrier gas/vapour stream is rapidly cooled to produce an oil condensation smoke with a particle size in the range of 0.2-2.0 #m. The thermal and process dynamics of the system have sufficiently large time constants to maintain a relatively close control on the smoke concentration.

87:6759 Melville, W.K. and K.R. Helfrich, 1987. Trans-

critical two-layer flow over topoffmphy. J. Fluid Mech., 178:31-52.

The evolution of weakly-nonlinear two-layer flow over bottom topography is considered. The gov- erning equations are formulated to consider the effects of quadratic and cubic nonlinearity in the transcritical regime of the internal mode. In that regime in which both quadratic and cubic nonlin- earity are comparable, evolution of the interface is described by an inhomogeneous extended Korte- weg-de Vries equation. MIT, Cambridge, MA 02139, USA.