Publications
71 results found
Dalziel SB, Hughes GO, Sutherland BR, 2000, Whole-field density measurements by 'synthetic schlieren', EXPERIMENTS IN FLUIDS, Vol: 28, Pages: 322-335, ISSN: 0723-4864
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- Citations: 261
Henley RW, Hughes GO, 2000, Underground fumaroles: 'Excess heat' effects in vein formation, Economic Geology, Vol: 95, Pages: 453-466, ISSN: 0361-0128
We examine the heat extracted from a fractured hydrothermal system following the sudden dilation of fractures in the host rock. This dilation increases the permeability of the system, and veins form along irregular fractures where the opening is localized. For simplicity, we will consider one such vein in this paper. Fluid in the system is assumed to be initially close to vapor saturation and in thermal equilibrium with the surrounding host rock. The rapid opening of the vein leads to approximately isenthalpic vapor separation and causes a pressure drop to propagate through the system. As the two-phase fluid in the fracture system is constrained to the vapor-pressure curve, the depressurization is accompanied by a rapid cooling of the fluid. Fluid flow is also induced from a hydrothermal reservoir toward the dilated discharge vein. The temperature difference between the host rock and the two-phase fluid in the fracture system drives heat from the rock into the fluid. The 'excess heat' derived from the host rock in this manner evaporates additional liquid in the two-phase flow, which develops substantially larger vapor fractions than those due only to the rapid initial adiabatic depressurization of the fluid. Such additional vapor separation, therefore, leads to high solute concentrations in the liquid phase and potentially results in faster deposition of minerals in the fracture system and local veins. A model is developed here to describe the minimum excess heat transfer (i.e., the worst-case scenario) into the two-phase saturated-liquid/vapor mixture as it is drawn horizontally from the hydrothermal reservoir toward the discharge vein. Excess heat effects are shown to be effective within tens to hundreds of meters of actively forming veins and a principal cause of oscillatory banding and lamination fabrics. This transient heat extraction process applies to a wide range of shallow crustal deposit styles associated with brittle and brittle-ductile deformation. These
Sutherland BR, Hughes GO, Dalziel SB, et al., 2000, Internal waves revisited, DYNAMICS OF ATMOSPHERES AND OCEANS, Vol: 31, Pages: 209-232, ISSN: 0377-0265
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- Citations: 23
Sutherland BR, Dalziel SB, Hughes GO, et al., 1999, Visualization and measurement of internal waves by 'synthetic schlieren'. Part 1. Vertically oscillating cylinder, JOURNAL OF FLUID MECHANICS, Vol: 390, Pages: 93-126, ISSN: 0022-1120
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- Citations: 138
Sutherland BR, Dalziel SB, Hughes GO, et al., 1998, Laboratory observations of internal waves, Pages: 855-858
We present measurements of the internal wavefield produced in a stratified fluid by a simple vertically oscillating cylinder. A novel digital image-processing technique known as 'synthetic-schlieren' (Sutherland et al., 1998) is described which allows the density and velocity fields to be determined by non-intrusive optical means. The synthetic-schlieren technique is used here to examine the effect of viscosity on the wavefield.
Stamp AP, Hughes GO, Nokes RI, et al., 1998, The coupling of waves and convection, JOURNAL OF FLUID MECHANICS, Vol: 372, Pages: 231-271, ISSN: 0022-1120
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- Citations: 16
Hughes GO, Nokes RI, 1995, ‘Wave-Convection Coupling’ in Multicomponent Convection: an Experimental Study., Double-diffusive convection, Editors: Brandt, Fernando, Phillips, Van Heijst, Publisher: Amer Geophysical Union, Pages: 49-56, ISBN: 9780875900766
Nokes RI, Hughes GO, 1994, Turbulent mixing in uniform channels of irregular cross-section, Journal of Hydraulic Research, Vol: 32, Pages: 67-86, ISSN: 0022-1686
A new method is presented for modelling three-dimensional turbulent dispersion problems in open channels with an arbitrary, but uniform, cross-section. The semi-analytical technique is applicable when investigating the steady discharge of effluent into a channel which has distributions of longitudinal velocity and turbulent diffusivities specified over its cross-section. Implementation of the method is discussed, along with an example illustrative of the effects of three-dimensional mixing. Predictions are also compared with the experimental results of Wood and Liang (1989) for mixing in a flood-plain/main channel geometry.
NOKES RI, HUGHES GO, 1994, TURBULENT MIXING IN UNIFORM CHANNELS OF IRREGULAR CROSS-SECTION, JOURNAL OF HYDRAULIC RESEARCH, Vol: 32, Pages: 67-86, ISSN: 0022-1686
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- Citations: 9
NOKES RI, HUGHES GO, 1992, POLLUTANT DISPERSION IN CHANNELS OF COMPLEX CROSS-SECTION, 11th Australasian Fluid Mechanics Conference, Publisher: UNIVERSITY TASMANIA, Pages: 925-928
Griffiths RW, Maher N, Hughes GO, Ocean stratification under oscillatory surface buoyancy forcing, JOURNAL OF MARINE RESEARCH, Vol: 69, Pages: 523-543, ISSN: 0022-2402
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- Citations: 3
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