Modelling tracer and particle transport under turbulent flow conditions
in karst conduit structures
A
computational fluid dynamics model (CFD) is used to calculate flow in
example-types of karst conduit geometries on a decametric scale. Simulations
of tracer experiments show the influence of conduit geometry on the tracer
breakthrough curve (BTC) on this scale. Tailing of the falling limb of
the curve can be observed and is due to tracer captured in stagnant water.
A new BTC fitting and interpretation method is developed. It is based
on an analytical solution of the transport equation and allows the quantification
of the tailing. The results of the numerical simulations are confirmed
by laboratory tracer experiments and field tests. The numerical flow solutions
are also used to predict deposition rates of suspended colloids and particles
in a karst aquifer.
A
computational fluid dynamics model (CFD) is used to calculate flow in
example-types of karst conduit geometries on a decametric scale. Simulations
of tracer experiments show the influence of conduit geometry on the tracer
breakthrough curve (BTC) on this scale. Tailing of the falling limb of
the curve can be observed and is due to tracer captured in stagnant water.
A new BTC fitting and interpretation method is developed. It is based
on an analytical solution of the transport equation and allows the quantification
of the tailing. The results of the numerical simulations are confirmed
by laboratory tracer experiments and field tests. The numerical flow solutions
are also used to predict deposition rates of suspended colloids and particles
in a karst aquifer.