The present paper reports a study conducted to examine several sands with a large spread of parti... more The present paper reports a study conducted to examine several sands with a large spread of particle size in order to validate the modelling of both Darcy's and Forchheimer's law parameters, which could be applied to any kind of sand. An experimental set-up has been specially conceived to generate hydraulic gradients within fine sands higher than 600. We also present an attempt at using a capillary-type flow model to determine structural parameters of sand and predict pressure gradients. The specific surface areas calculated appear to be consistent with surface areas estimated from screening experiments. Similarly, tortuosity values calculated from pressure drop experiments stand within the range of values found in the literature, measured using an alternative method, the conductometric method. Using one dimensionless equation of the capillary-type flow model, a single value of the pore Reynolds number makes it possible to determine, whatever the porous medium, the limits of Darcy's flow regime. This Reynolds number value is 4.3.
Water flow in porous media has many applications in terrestrial, fluvial and marine structures. I... more Water flow in porous media has many applications in terrestrial, fluvial and marine structures. In the marine field, this flow is induced by waves and tides which can provoke high and transient pressure. Internal flow induced by waves in porous structures influences their mechanical behaviour. Various authors work on numerical modelling of stability of these structures (rubble mound breakwaters, ...). The internal flow modelling needs transient flow laws which can be obtained by laboratory experiments that are very limited. The present paper reports an experimental set-up and results analysis conducted to determine transient flow laws in several marine porous media. Permeameter and test station have been especially developed for this study. A forced water flow going through the soil sample within the test cell, is provoked by a pump supplied from a tank. The order signal (amplitude and period of wave) is treated by PID that maintains a regulated circuit. We use an automatic regulated gate to simulate internal waves (period between 5 seconds and 15 seconds). The pressure drop is measured by pressure differential gauges. The flow-rate is measured by electromagnetic flow-meter. The setting is connected to a computer data logger.
The present paper reports a study conducted to examine several sands with a large spread of parti... more The present paper reports a study conducted to examine several sands with a large spread of particle size in order to validate the modelling of both Darcy's and Forchheimer's law parameters, which could be applied to any kind of sand. An experimental set-up has been specially conceived to generate hydraulic gradients within fine sands higher than 600. We also present an attempt at using a capillary-type flow model to determine structural parameters of sand and predict pressure gradients. The specific surface areas calculated appear to be consistent with surface areas estimated from screening experiments. Similarly, tortuosity values calculated from pressure drop experiments stand within the range of values found in the literature, measured using an alternative method, the conductometric method. Using one dimensionless equation of the capillary-type flow model, a single value of the pore Reynolds number makes it possible to determine, whatever the porous medium, the limits of Darcy's flow regime. This Reynolds number value is 4.3.
The present paper reports a study conducted to examine several sands with a large spread of parti... more The present paper reports a study conducted to examine several sands with a large spread of particle size in order to validate the modelling of both Darcy's and Forchheimer's law parameters, which could be applied to any kind of sand. An experimental set-up has been specially conceived to generate hydraulic gradients within fine sands higher than 600. We also present an attempt at using a capillary-type flow model to determine structural parameters of sand and predict pressure gradients. The specific surface areas calculated appear to be consistent with surface areas estimated from screening experiments. Similarly, tortuosity values calculated from pressure drop experiments stand within the range of values found in the literature, measured using an alternative method, the conductometric method. Using one dimensionless equation of the capillary-type flow model, a single value of the pore Reynolds number makes it possible to determine, whatever the porous medium, the limits of Darcy's flow regime. This Reynolds number value is 4.3.
Abstract The relationship between the growth speed and wood properties of Pinus merkusii was inve... more Abstract The relationship between the growth speed and wood properties of Pinus merkusii was investigated using 34-year-old trees planted in Indonesia in an attempt to promote the establishment of plantation of this species. The trees in the test plot were categorized as ...
The relationships between growth characteristics and wood properties were investigated for a thre... more The relationships between growth characteristics and wood properties were investigated for a threatened species, Pericopsis mooniana, to promote the establishment of plantations of this species in the tropics. Growth characteristics (diameter and height) and stress-wave velocity (SWV) of trees were measured for 22-year-old P. mooniana trees planted in Indonesia. The trees were categorized into three groups, fast-growing, middle-growing, and slow-growing trees, to investigate the effect of growth rate on the wood properties. In addition, radial variation of anatomical characteristics and wood properties were determined. No significant correlation was found between growth characteristics and SWV. The values for the vessel diameter, cell wall thickness of wood fibers, wood fiber length, basic density, modulus of elasticity, and modulus of rupture from wood at the bark side were higher than those at the pith side. On the other hand, vessel frequency gradually decreased from pith to bark. These results suggested that low-quality wood, such as juvenile wood, existed near the pith area.
The present paper reports a study conducted to examine several sands with a large spread of parti... more The present paper reports a study conducted to examine several sands with a large spread of particle size in order to validate the modelling of both Darcy's and Forchheimer's law parameters, which could be applied to any kind of sand. An experimental set-up has been specially conceived to generate hydraulic gradients within fine sands higher than 600. We also present an attempt at using a capillary-type flow model to determine structural parameters of sand and predict pressure gradients. The specific surface areas calculated appear to be consistent with surface areas estimated from screening experiments. Similarly, tortuosity values calculated from pressure drop experiments stand within the range of values found in the literature, measured using an alternative method, the conductometric method. Using one dimensionless equation of the capillary-type flow model, a single value of the pore Reynolds number makes it possible to determine, whatever the porous medium, the limits of Darcy's flow regime. This Reynolds number value is 4.3.
Water flow in porous media has many applications in terrestrial, fluvial and marine structures. I... more Water flow in porous media has many applications in terrestrial, fluvial and marine structures. In the marine field, this flow is induced by waves and tides which can provoke high and transient pressure. Internal flow induced by waves in porous structures influences their mechanical behaviour. Various authors work on numerical modelling of stability of these structures (rubble mound breakwaters, ...). The internal flow modelling needs transient flow laws which can be obtained by laboratory experiments that are very limited. The present paper reports an experimental set-up and results analysis conducted to determine transient flow laws in several marine porous media. Permeameter and test station have been especially developed for this study. A forced water flow going through the soil sample within the test cell, is provoked by a pump supplied from a tank. The order signal (amplitude and period of wave) is treated by PID that maintains a regulated circuit. We use an automatic regulated gate to simulate internal waves (period between 5 seconds and 15 seconds). The pressure drop is measured by pressure differential gauges. The flow-rate is measured by electromagnetic flow-meter. The setting is connected to a computer data logger.
The present paper reports a study conducted to examine several sands with a large spread of parti... more The present paper reports a study conducted to examine several sands with a large spread of particle size in order to validate the modelling of both Darcy's and Forchheimer's law parameters, which could be applied to any kind of sand. An experimental set-up has been specially conceived to generate hydraulic gradients within fine sands higher than 600. We also present an attempt at using a capillary-type flow model to determine structural parameters of sand and predict pressure gradients. The specific surface areas calculated appear to be consistent with surface areas estimated from screening experiments. Similarly, tortuosity values calculated from pressure drop experiments stand within the range of values found in the literature, measured using an alternative method, the conductometric method. Using one dimensionless equation of the capillary-type flow model, a single value of the pore Reynolds number makes it possible to determine, whatever the porous medium, the limits of Darcy's flow regime. This Reynolds number value is 4.3.
The present paper reports a study conducted to examine several sands with a large spread of parti... more The present paper reports a study conducted to examine several sands with a large spread of particle size in order to validate the modelling of both Darcy's and Forchheimer's law parameters, which could be applied to any kind of sand. An experimental set-up has been specially conceived to generate hydraulic gradients within fine sands higher than 600. We also present an attempt at using a capillary-type flow model to determine structural parameters of sand and predict pressure gradients. The specific surface areas calculated appear to be consistent with surface areas estimated from screening experiments. Similarly, tortuosity values calculated from pressure drop experiments stand within the range of values found in the literature, measured using an alternative method, the conductometric method. Using one dimensionless equation of the capillary-type flow model, a single value of the pore Reynolds number makes it possible to determine, whatever the porous medium, the limits of Darcy's flow regime. This Reynolds number value is 4.3.
Abstract The relationship between the growth speed and wood properties of Pinus merkusii was inve... more Abstract The relationship between the growth speed and wood properties of Pinus merkusii was investigated using 34-year-old trees planted in Indonesia in an attempt to promote the establishment of plantation of this species. The trees in the test plot were categorized as ...
The relationships between growth characteristics and wood properties were investigated for a thre... more The relationships between growth characteristics and wood properties were investigated for a threatened species, Pericopsis mooniana, to promote the establishment of plantations of this species in the tropics. Growth characteristics (diameter and height) and stress-wave velocity (SWV) of trees were measured for 22-year-old P. mooniana trees planted in Indonesia. The trees were categorized into three groups, fast-growing, middle-growing, and slow-growing trees, to investigate the effect of growth rate on the wood properties. In addition, radial variation of anatomical characteristics and wood properties were determined. No significant correlation was found between growth characteristics and SWV. The values for the vessel diameter, cell wall thickness of wood fibers, wood fiber length, basic density, modulus of elasticity, and modulus of rupture from wood at the bark side were higher than those at the pith side. On the other hand, vessel frequency gradually decreased from pith to bark. These results suggested that low-quality wood, such as juvenile wood, existed near the pith area.
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