scholarly journals Role of Hydraulic Conductivity Uncertainties in Modeling Water Flow through Forest Watersheds

10.5772/56900 ◽  
2013 ◽  
Author(s):  
Marie-France Jutras ◽  
Paul A.
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Forest Watersheds ◽  
Flow Through

Joint estimation of hydraulic conductivities of two sand samples in a W-tube system with a bi-exponential response

2015 ◽  
Vol 47 (2) ◽  
pp. 344-355 ◽  
Author(s):  
Mariusz Kaczmarek ◽  
Filip Wolny ◽  
Marek Marciniak
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Optimization Procedure ◽  
Joint Estimation ◽  
Exponential Rate ◽  
Tube System ◽  
Two Samples ◽  
Independent Constant ◽  
Flow Through ◽  
Constant Head

The motivation for this paper is the practical problem of interpreting bi-exponential rate-of-rise curves that are observed during many field piezometric tests. In the authors' previous study, a laboratory W-tube system of water flow through two samples of sand was introduced with an adequate mathematical model. The desired bi-exponential character of water flow was obtained by placing two different samples of sand in separate but connected columns. In the present paper, a so-called inverse problem is solved. The optimization procedure is applied in order to jointly estimate a pair of hydraulic conductivity values based on experimentally recorded bi-exponential rate-of-rise curves. The obtained values of hydraulic conductivities are presented and compared to the values determined from independent constant-head permeability tests conducted for the analyzed sands. The results of this identification procedure varied in accuracy. The mean percent errors between the hydraulic conductivity values measured jointly and independently for the analyzed experimental series were in the range of 8.8 to 37.2%. The discussion presents the restrictions of this interpretational method and suggests further modeling plans.

Resistance to water flow in Fagus grandifolia leaves

1977 ◽  
Vol 55 (20) ◽  
pp. 2591-2599 ◽  
Author(s):  
M. T. Tyree ◽  
Y. N. S. Cheung
Keyword(s):  
Hydraulic Conductivity ◽  
Water Flow ◽  
Shortest Path ◽  
Activation Energies ◽  
Fagus Grandifolia ◽  
Xylem Vessel ◽  
Mesophyll Cells ◽  
Water Efflux ◽  
Flow Through ◽  
Pressure Driven

The tempo of water efflux from single Fagus grandifolia leaves has been measured. The resistance to pressure-driven water efflux has been measured for normal leaves, Rs, and for leaves in which extracellular mesophyll spaces are infiltrated with water, Rs*. The ratio Rs*/Rs is about 0.4. The resistance to water flow through the xylem, Rx, was also measured and found to be a small part of Rs, i.e., Rx/Rs = 0.08. The activation energies for water efflux from normal and infiltrated leaves are both about 26 ± 4 kJ/mol.After an analysis of our data, we conclude that the membrane hydraulic conductivity of F. grandifolia leaves is roughly 10−6 cm s−1 bar−1 (1 bar = 100 kPa) and that water travels the shortest path between the cell sap and the nearest xylem vessel, flowing in and out of mesophyll cells through the areas in contact between adjacent cells along the pathway.

Cavitation in an Extremely Limited Flow Through Very Small Orifices

1982 ◽  
Vol 104 (1) ◽  
pp. 94-98 ◽  
Author(s):  
R. Oba ◽  
T. Ikohagi ◽  
K. T. Kim
Keyword(s):  
Turbulent Flows ◽  
Water Flow ◽  
Cavitation Number ◽  
Orifice Diameter ◽  
Flow Through ◽  
Cavitation Nuclei ◽  
Technical Interest

In order to clarify the role of cavitation nuclei upon inception, the behavior of inception was carefully investigated in an extremely limited water flow through very small orifices less than 1.0 mm in diameter under a prescribed nuclei condition. The following facts of technical interest were determined: a) The desinent cavitation number (σd) decreased rapidly and exponentially with the orifice diameter d, up to one hundredth in magnitude; and b) the cavitation appearance in such limited flows was quite different from that in fully turbulent flows through larger orifices.

HEAT TRANSFER BURNOUT IN WATER FLOW THROUGH ROUND TUBES AND ANNULI

1970 ◽  
Author(s):  
B. A. Zenkevich ◽  
P. L. Kirillov ◽  
G. V. Alekseev ◽  
O. L. Peskov ◽  
O. A. Sudnitsyn
Keyword(s):  
Heat Transfer ◽  
Water Flow ◽  
Flow Through

Modeling of Reduced Water Flow through Concrete Caused by Crystallization Technology

2006 ◽  
Vol 9 (8) ◽  
pp. 723-730
Author(s):  
Abdelaziz Al-Khlaifat ◽  
Awni Al-Otoom
Keyword(s):  
Water Flow ◽  
Flow Through ◽  
Reduced Water

Saturated Hydraulic Conductivity of Clayey Tills and the Role of Fractures

1990 ◽  
Vol 21 (2) ◽  
pp. 119-132 ◽  
Author(s):  
Johnny Fredericia
Keyword(s):  
Hydraulic Conductivity ◽  
American Studies ◽  
Field Measurements ◽  
Present Knowledge ◽  
Saturated Hydraulic Conductivity ◽  
Field Observations ◽  
Laboratory Measurements ◽  
Vertical Hydraulic Conductivity ◽  
Data Field

The background for the present knowledge about hydraulic conductivity of clayey till in Denmark is summarized. The data show a difference of 1-2 orders of magnitude in the vertical hydraulic conductivity between values from laboratory measurements and field measurements. This difference is discussed and based on new data, field observations and comparison with North American studies, it is concluded to be primarily due to fractures in the till.

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