This simulator shows a saturated porous aquifer bounded by fixed hydraulic heads on the left and right. Change hydraulic conductivity, the two boundary heads, effective porosity and the flow-path length, and compare Darcy flux with the faster average pore-water velocity and the tracer travel time.
• A real-time 3D scene with 5 inspectable parts (Saturated porous aquifer, Low-permeability base, Boundary piezometers, Pore-water flow paths and Conservative tracer marker), with home view, focus-selected-part, auto-rotate, expand, instrument-cover and hide-labels scene tools, plus a model response curve beneath the scene. • Experiment controls: Hydraulic conductivity (0.5-20 m/day); Left hydraulic head (10-30 m); Right hydraulic head (10-30 m); Effective porosity (0.1-0.4); Flow-path length (50-200 m); show explanatory motion markers; pause/resume, 0.1 s and 1 s single-step buttons, four playback speeds and a restart button. • A Curves & measurements tab with a parameter-comparison chart, a live-measurements chart, the model equations and snapshot readouts (Signed head gradient; Darcy flux left → right; Average pore velocity; Discharge through100 m²; Advective travel time). • An Experiments tab with 2 guided presets (reverse the gradient and equal heads) and a Model verification bench that runs independent fresh models, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with guided lessons, a knowledge-check quiz with reset and a written model-scope statement linking to a technical reference.
The head gradient is i = (hLeft - hRight) / L, and Darcy flux is q = K i, so flow goes from higher to lower hydraulic head. Average pore velocity is v = q / ne, larger than q because water moves only through the pore fraction. Discharge through a 100 square meter cross-section is Q = q A, and advective travel time is L / |v|.
The lab reports the signed gradient, flux, pore velocity, discharge and travel time.
Reversing the boundary heads reverses the flow direction, and equal heads give zero gradient, zero flow and an infinite advective travel time. Darcy flux is generally not equal to pore velocity.
The model is steady, homogeneous, saturated one-dimensional flow with fixed boundary heads and constant area. The drawn flow paths are conceptual, and it includes no pumping cone, unsaturated flow, diffusion or dispersion.
Generally no. Pore velocity is the Darcy flux divided by effective porosity, so it is faster than the flux because water travels only through the open pore space.
Toward lower hydraulic head. Head includes pressure and elevation contributions, and the reverse-the-gradient experiment swaps the boundary heads to flip the direction.
The gradient is zero, so there is no flow and the advective travel time is infinite. The equal-heads experiment shows this.
No. It is steady, homogeneous, saturated one-dimensional flow. It omits pumping cones, unsaturated flow, diffusion and dispersion.