Browsing by Author "Olowofela, J. A."

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Determination of transition length in flow through porous sand material
(2009) Adegoke, J. A.; Olowofela, J. A.
A transition length is normally observed when fluid flows through a conduit before laminar flow is accomplished. This work examined a situation whereby porous materials were filled into the conduit and fluid was made to flow through. An attempt was made to determine this transition length for flow of water through riverbed sand of varying porosities filled into a horizontal cylindrical pipe of diameter 0.345 x 102m with piezometric water head, set at 0.06m. The transition length was observed to be constant for the samples considered and it occurred at 0.60m from the point of entrance; nevertheless, values of pressure at this point increases with increase in porosity.
Effects of clay content and porosity on wave velocities in unconsolidated media wing empirical relations
(Nanjing Institute of Geophysical Prospecting, 2004) Olowofela, J. A.; Kamiyole, I. C.; Adegoke, J. A.
"Wave velocities in sandstones are greatly influenced by porosity and clay contents. We formulated new empirical relations for the velocities Vp and Vs in these media which take into account the porosity and clay contents. These relations are Vp=5.57 - 6.47ø - 2.27C1 ø and Vx=3.41 - 4.44ø - 2.23C1 ø, and can be used to compute velocitiesfor various porosities and clay contents. The result compare favourably with those of other works. "
A laboratory study of the effects of porosity and bed tilting on the discharge rate of groundwater
(Springer India, 2005) Olowofela, J. A.; Adegoke, J. A.
The study of movement of underground water helps to predict the extent of flow in as much as we can determine the volume rate among other things. Sand samples from river bed were used as porous media, a laboratory experiment was set up to look at longitudinal dispersion in term of volume of liquid flowing across a unit cross sectional area per unit time in these materials. Water was made to flow through a cylindrical pipe drilled sideways at intervals. Values of pressure were taken at regular interval and using appropriate basic equations, the volume flux rate was determined at various angles of tilt, from which volume rate of flow was also determined. A graph of volume rate of flow against angle of tilt gives the value of volume rate of flow as 1.00 ' 10-10 m3/s irrespective of porosity and permeability of the medium provided that the angle of tilt is 1.42°
Modelling effective rheologies for viscoelastic porous media with application to silt, and medium coarse sand
(Nanjing Institute of Geophysical Prospecting, 2004) Olowofela, J. A.; Adegoke, J. A.
A modification of Biot's poroelastic differential equations is made to include matrix-fluid interaction mechanisms which assume a solid-fluid relaxation function coupling coefficient. Values of physical properties of sediments are incorporated into equations which define phase velocity and attenuation for porous media which are dependent on the composite densities of various media (silt, and medium and coarse sand). The results enable us to compare the attenuation and velocities of waves in these media. We observed that the density of coarse sand is greater than that of medium sand and this in turn is greater than that of silt-the same holds-for the velocities of P-waves in these media but the situation is converse for shear waves in the same given media. As the densities of the media increase, their attenuation decreases as it was found that the attenuation of silt is the highest and that of coarse sand lowest for the media considered.
Variability of permeability with diameter of conduit
(Indian Academy of Sciences, 2008) Adegoke, J. A.; Olowofela, J. A.
"An entry length is always observed before laminar flow is achieved in fluid flowing in a conduit. This depends on the Reynolds number of the flow and the degree of smoothness of the conduit. This work examined this region and the point where laminar flow commences in the context of flow through conduit packed with porous material like beads, of known porosity. Using some theoretical assumptions, it is demonstrated that permeability varies from zero at wall-fluid boundary to maximum at mid-stream, creating a permeability profile similar to the velocity profile. An equation was obtained to establish this. We also found that peak values of permeability increase with increasing porosity, and therefore entry length increases with increasing porosity with all other parameters kept constant. A plot of peak permeability versus porosity revealed that they are linearly related. "