Gravity currents created by the release of a fixed volume of a suspens
ion into a lighter ambient fluid are studied theoretically and experim
entally. The greater density of the current and the buoyancy force dri
ving its motion arise primarily from dense particles suspended in the
interstitial fluid of the current. The dynamics of the current are ass
umed to be dominated by a balance between inertial and buoyancy forces
, viscous forces are assumed negligible. The currents considered are t
wo-dimensional and flow over a rigid horizontal surface. The flow is m
odelled by either the single- or the two-layer shallow-water equations
, the two-layer equations being necessary to include the effects of th
e overlying fluid, which are important when the depth of the current i
s comparable to the depth of the overlying fluid. Because the local de
nsity of the gravity current depends on the concentration of particles
, the buoyancy contribution to the momentum balance depends on the var
iation of the particle concentration. A transport equation for the par
ticle concentration is derived by assuming that the particles are vert
ically well-mixed by the turbulence in the current, are advected by th
e mean flow and settle out through the viscous sublayer at the bottom
of the current. The boundary condition at the moving front of the curr
ent relates the velocity and the pressure head at that point. The resu
lting equations are solved numerically, which reveals that two types o
f shock can occur in the current. In the late stages of all particle-d
riven gravity currents, an internal bore develops that separates a par
ticle-free jet-like flow in the rear from a dense gravity-current flow
near the front. The second type of bore occurs if the initial height
of the current is comparable to the depth of the ambient fluid. This b
ore develops during the early lock-exchange flow between the two fluid
s and strongly changes the structure of the cur-rent and its transport
of particles from those of a current in very deep surroundings. To te
st the, theory, several experiments were performed to measure the leng
th of particle-driven gravity currents as a function of time and their
deposition patterns for a variety of particle sizes and initial masse
s of sediment. The comparison between the theoretical predictions, whi
ch have no adjustable parameters, and the experimental results are ver
y good.