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Read Full Article (file size: 499721 bytes) Cited by
WATER RESOURCES RESEARCH,
VOL. 44,
W03501,
doi:10.1029/2007WR006601,
2008
Effects of turbulence on hydraulic heads and parameter sensitivities in preferential groundwater flow layers
W. Barclay Shoemaker
U.S. Geological Survey, Fort Lauderdale, Florida, USA
Kevin J. Cunningham
U.S. Geological Survey, Fort Lauderdale, Florida, USA
Eve L. Kuniansky
U.S. Geological Survey, Norcross, Georgia, USA
Joann Dixon
U.S. Geological Survey, Fort Lauderdale, Florida, USA
Abstract
A conduit flow process (CFP) for the Modular Finite Difference Ground-Water Flow model, MODFLOW-2005, has been created by
the U.S. Geological Survey. An application of the CFP on a carbonate aquifer in southern Florida is described; this application
examines (1) the potential for turbulent groundwater flow and (2) the effects of turbulent flow on hydraulic heads and parameter
sensitivities. Turbulent flow components were spatially extensive in preferential groundwater flow layers, with horizontal
hydraulic conductivities of about 5,000,000 m d−1, mean void diameters equal to about 3.5 cm, groundwater temperature equal to about 25°C, and critical Reynolds numbers less
than or equal to 400. Turbulence either increased or decreased simulated heads from their laminar elevations. Specifically,
head differences from laminar elevations ranged from about −18 to +27 cm and were explained by the magnitude of net flow to
the finite difference model cell. Turbulence also affected the sensitivities of model parameters. Specifically, the composite-scaled
sensitivities of horizontal hydraulic conductivities decreased by as much as 70% when turbulence was essentially removed.
These hydraulic head and sensitivity differences due to turbulent groundwater flow highlight potential errors in models based
on the equivalent porous media assumption, which assumes laminar flow in uniformly distributed void spaces.
Received 18
October
2007;
accepted 18
December
2007;
published 29
March
2008.
Keywords: conduit flow;
turbulent flow;
karst hydrology.
Index Terms: 1805 Hydrology: Computational hydrology; 1829 Hydrology: Groundwater hydrology; 1847 Hydrology: Modeling; 1849 Hydrology: Numerical approximations and analysis.
Read Full Article (file size: 499721 bytes) Cited by
Citation: Shoemaker, W. B., K. J. Cunningham, E. L. Kuniansky, and J. Dixon
(2008),
Effects of turbulence on hydraulic heads and parameter sensitivities in preferential groundwater flow layers,
Water Resour. Res.,
44,
W03501,
doi:10.1029/2007WR006601.
Copyright 2008 by the American Geophysical Union.
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