Experimental Investigation of Internal Drag Force by Creeping Flow in Macro-porous Media

The study of fluid flow through porous media is mostly taken place in number of technical areas including groundwater flows, flow through embankment dams, initiation channelized debris flow, filtering, and bio-fluid flow. The prior studies densely focused on the influence of Reynolds number flows through the porous media. The particular studies of above-mentioned case gravitated to the theme of steady and unsteady state, permeability, flow regime, macro-seepage equation and microscopic characteristic equation, yet less attention on the study of drag force of the creeping flow at low Reynolds number. This phenomenon occurs at low flow rate of the fluid flow through porous media, which is associated with the natural flow rate in ground water flow. In this study, drag force was investigated under the low water flow rate through macro-porous media in the cylindrical water circulation type drag measurement device, having an inner diameter of 404 mm and lengths of 100 mm, 300 mm, and 500 mm containing sphere glass balls of the diameters of 1.7 cm, 2.45 cm, and 3.3 cm alternatively, and the outer diameter of the tube was 600 mm. The maximum measurement load of the loadcell is 10 kg. The initial conditions of the load measurement were given 0.5 kg, 1 kg, 1.5 kg, 2 kg, and 2.5 kg with the number of Rotational Pump Monitor (RPM) of 50 to 450 by increasing 50 within 2 minutes interval. The relationship between the drag force and Reynolds number, velocity, and so forth were analyzed. The existence of the remarkable deviation range of the scatter plots at creeping flow occurred while the drag forces increased consistently at high flow rate. Considering these results, the inspection on this phenomenon proposed to test if there are various flow regimes in porous media or technical errors. Based on experimental data, the creeping water flow through macro-porous media will be interpreted by using Reynolds number-drag force curve. The flow behavior, trend curves at low flow rate and apparatus specification conditions were investigated.

Keywords: Macro-porous media, Drag force, Low Reynolds number, Creeping flow