Modeling Of Turbidity Currents Research Articles

Hydrodynamics of turbidity currents evolving over a plane bed

In this paper, we investigate the hydrodynamics of turbidity currents evolving over a plane bed. The analytical framework encompasses the depth-averaged conservation equations for fluid mass, sediment mass, momentum, and turbulent kinetic energy (TKE). The analysis incorporates self-similar distributions of streamwise velocity, sediment concentration, and TKE. Using the self-similar distributions of streamwise velocity and sediment concentration, the distributions of turbulent diffusivity, Reynolds shear stress, and TKE production rate are determined. The analytical model of turbidity currents enables the prediction of streamwise evolutions of flow depth, depth-averaged velocity, depth-averaged sediment concentration, and depth-averaged TKE. The self-acceleration and subsidence of turbidity currents are found to depend on the initial conditions. Additionally, the model results demonstrate the sensitivity of turbidity current hydrodynamics to grain size and longitudinal bed slope. Importantly, increased grain size and longitudinal bed slope contribute to enhanced self-acceleration, leading to a decrease in the subsidence rate of turbidity currents. The model predictions satisfactorily capture the available experimental data.

Development of multiphase solver for the modeling of turbidity currents (the case study of Dez Dam)

Dams in semi-arid regions, like Iran's Dez dam, are losing their capacity by sedimentation. Settling sediments reduces clear water, and hydropower plants' efficiency. Reservoir sedimentation relies on turbidity currents (TC). TC head velocity, and sediment content both affect particle tracking, and the removal from reservoirs. To comprehend the TC properties of Dez dam reservoir, large-scale TC modeling is required. To represent large-scale TC, a novel solver is developed. This solver couples a modified OpenFOAM® interFoam solver with the particle concentration transport equation. Two experimental tests, and Dez dam field data were verified and calibrated. The novel solution modeled these instances utilizing a two-dimensional vertical model (width averaged) with RANS turbulence closure, despite the fact that the Dez dam reservoir has a considerable size for numerical modeling. The solver simulated four Dez Dam reservoir scenarios with different water levels. Consequently, when the inlet water depth rose four times, the TC head velocity, and distance traveled by TC doubled. TC in Dez dam is a supercritical flow with the interface instabilities based on its local Richardson number, and gradient Richardson number. Furthermore, Kelvin-Helmholtz instabilities and recirculation vortex combine clear water with TC to reduce the particle concentration.

Forward-modeling of co-evolution of turbidity currents, sediment transport, and cyclic steps in the Rio Muni Basin

Previous quantitative studies of field-scale cyclic steps are mostly based on analysis of field data. Such studies have shed light on the erosion/deposition patterns over these morphological features as well as the magnitudes of the turbidity current parameters back estimated using the measured geometry data. However, it remains unclear to what extent such back estimated hydraulic features and erosion/deposition patterns can be numerically reproduced by process-based numerical models. Here, a two-dimensional layer-averaged fully coupled turbidity current model is applied to forward-model co-evolution of turbidity currents, sediment transport, and cyclic steps in the Rio Muni Basin off the West Africa margin, where nine cyclic steps featuring a transition from the upstream erosion to the downstream deposition were identified. Numerical case studies indicate that large and bankfull turbidity currents do not form the erosion-deposition transition because they are likely to fall into the high-speed regime that favors whole-scale erosion. In this regard, threshold values for the current velocity were derived to distinguish high/low-speed regimes of turbidity currents. It is shown that smaller turbidity currents, which do not follow the bankfull assumption, and, thus, fall into the low-speed turbidity current regime, may produce cyclic steps by current deceleration. While values of the derived physical parameters of the smaller turbidity current differ quantitatively from those of previous back estimated values, their qualitative variation trends are basically the same.

Prediction of flow and sediment transport rates into closed-end channels for turbidity current intrusion

Turbidity current intrusion often occurs in canals, approach channels and tributary areas of large reservoirs, causing sedimentation problems in these environments. Many models and semi-empirical equations have been proposed to calculate flow and sediment transport rates for turbidity current intrusion, under an assumption that the current front can keep propagating freely in the channel before dying out, but the effect of the finite length of closed-end channels has rarely been considered. A self-similar solution to the vertical two-dimensional model for turbidity currents is used to obtain the equation of the maximum possible length for the intrusion of turbidity currents. The maximum possible length is then used to modify an existing discharge equation for turbidity current intrusion in long channels and establish a more general calculation method that can be applied for intrusion in closed end channels. Data from two existing flume experiments are used to calibrate the derived equation of sediment transport rate for turbidity current intrusion. Field measurements obtained from several tributary mouths in the Xiaolangdi Reservoir are also used to calibrate the derived intrusion discharge equation. The agreement between predictions and observations, as well as the comparison between the proposed calculation method and the one before modification, demonstrate that the intrusion discharge is not only determined by the depth of turbid water and sediment concentration at the inlet of the tributary channel, but also influenced by the ratio of the real intrusion length to the maximum possible intrusion length.

Inverse modeling of turbidity currents using an artificial neural network approach: verification for field application

Abstract. Although in situ measurements in modern frequently occurring turbidity currents have been performed, the flow characteristics of turbidity currents that occur only once every 100 years and deposit turbidites over a large area have not yet been elucidated. In this study, we propose a method for estimating the paleo-hydraulic conditions of turbidity currents from ancient turbidites by using machine learning. In this method, we hypothesize that turbidity currents result from suspended sediment clouds that flow down a steep slope in a submarine canyon and into a gently sloping basin plain. Using inverse modeling, we reconstruct seven model input parameters including the initial flow depth, the sediment concentration, and the basin slope. A reasonable number (3500) of repetitions of numerical simulations using a one-dimensional layer-averaged model under various input parameters generates a dataset of the characteristic features of turbidites. This artificial dataset is then used for supervised training of a deep-learning neural network (NN) to produce an inverse model capable of estimating paleo-hydraulic conditions from data on the ancient turbidites. The performance of the inverse model is tested using independently generated datasets. Consequently, the NN successfully reconstructs the flow conditions of the test datasets. In addition, the proposed inverse model is quite robust to random errors in the input data. Judging from the results of subsampling tests, inversion of turbidity currents can be conducted if an individual turbidite can be correlated over 10 km at approximately 1 km intervals. These results suggest that the proposed method can sufficiently analyze field-scale turbidity currents.

Active faulting controls bedform development on a deep-water fan

Abstract Tectonically controlled topography influences deep-water sedimentary systems. Using 3-D seismic reflection data from the Levant Basin, eastern Mediterranean Sea, we investigate the spatial and temporal evolution of bedforms on a deep-water fan cut by an active normal fault. In the footwall, the fan comprises cyclic steps and antidunes along its axial and external portions, respectively, which we interpret to result from the spatial variation in flow velocity due to the loss of confinement at the canyon mouth. Conversely, in the hanging wall, the seafloor is nearly featureless at seismic scale. Numerical modeling of turbidity currents shows that the fault triggers a hydraulic jump that suppresses the flow velocity downstream, which thus explains the lack of visible bedforms basinward. This study shows that the topography generated by active normal faulting controls the downslope evolution of turbidity currents and the associated bedforms and that seafloor geomorphology can be used to evince syn-tectonic deposition.

A Numerical Study on Impacts of Sediment Erosion/Deposition on Debris Flow Propagation

Debris flows tend to erode sediment from or deposit sediment on the bed, which changes their volume and, thus, in turn, affects their rheological properties. However, previous modeling studies on debris flows mostly ignore sediment erosion/deposition. Here, three models are presented: a debris model without bed deformation, which is similar to traditional models in that it does not consider sediment erosion/deposition but uses the Herschel–Bulkley formulation to describe the non-Newtonian nature; a debris model with bed deformation, which is better improved than the traditional model in that it considers sediment erosion/deposition; and a turbidity current model, which is further simplified from the debris model with bed deformation by ignoring the non-Newtonian nature. These models, formulated in the same modeling framework, are solved by a shock-capturing finite volume method. These models were firstly validated against three laboratory experiments, which indicated that the debris models with and without bed deformation with reasonably well-specified parameters can give satisfactory agreements with the measurements, whereas the turbidity current model overestimated the experimental result due to its lack of yield stress and dynamic viscosity. Moreover, a hypothetical field application was used to explain the difference between a turbidity current and debris flows with and without bed deformation. It was shown that debris flows and turbidity currents are capable of impacting the bed significantly. However, turbidity currents have thinner tails, less shear stress, and form horizontal deposits on the bed, while debris flows have a thicker tail, high shear stress, and form vertical deposits on the bed. Finally, sensitivity analyses were carried out to study the impact of sediment size, bed slope, concentration, and porosity on the deformation of the bed after debris flow where they all showed a positive correlation.

The Influence of Confining Topography Orientation on Experimental Turbidity Currents and Geological Implications

Turbidity currents distribute sediment across the seafloor, forming important archives of tectonic and climatic change on the Earth’s surface. Turbidity current deposition is affected by seafloor topography, therefore understanding the interaction of turbidity currents with topography increases our ability to interpret tectonic and climatic change from the stratigraphic record. Here, using Shields-scaled physical models of turbidity currents, we aim to better constrain the effect of confining topography on turbidity current deposition and erosion. The subaqueous topography consists of an erodible barrier orientated 1) parallel, 2) oblique and 3) perpendicular to the incoming flow. An unconfined control run generated a supercritical turbidity current that decelerated across the slope, forming a lobate deposit that thickened basinwards before abruptly thinning. Flow-parallel confinement resulted in erosion of the barrier by the flow, enhanced axial velocities, and generated a deposit that extended farther into the basin than when unconfined. Oblique confinement caused partial deflection and acceleration of the flow along the barrier, which resulted in a deposit that bifurcated around the barrier. Forced deceleration at the barrier resulted in thickened deposition on the slope. Frontal confinement resulted in onlap and lateral spreading at the barrier, along with erosion of the barrier and down-dip overspill that formed a deposit deeper in the basin. Acceleration down the back of the barrier by this overspill resulted in the generation of a plunge-pool at the foot of the barrier as the flow impacted the slope substrate. Observations from ancient and modern turbidity current systems can be explained by our physical models, such as: the deposition of thick sandstones upstream of topography, the deposition of thin sandstones high on confining slopes, and the complex variety of stacking patterns produced by confinement. These models also highlight the impact of flow criticality on confined turbidity currents, with topographically-forced transitions between supercritical and subcritical flow conditions suggested to impact the depositional patterns of these flows.

Data-Driven, Multi-Model Workflow Suggests Strong Influence from Hurricanes on the Generation of Turbidity Currents in the Gulf of Mexico

Turbidity currents deliver sediment rapidly from the continental shelf to the slope and beyond; and can be triggered by processes such as shelf resuspension during oceanic storms; mass failure of slope deposits due to sediment- and wave-pressure loadings; and localized events that grow into sustained currents via self-amplifying ignition. Because these operate over multiple spatial and temporal scales, ranging from the eddy-scale to continental-scale; coupled numerical models that represent the full transport pathway have proved elusive though individual models have been developed to describe each of these processes. Toward a more holistic tool, a numerical workflow was developed to address pathways for sediment routing from terrestrial and coastal sources, across the continental shelf and ultimately down continental slope canyons of the northern Gulf of Mexico, where offshore infrastructure is susceptible to damage by turbidity currents. Workflow components included: (1) a calibrated simulator for fluvial discharge (Water Balance Model - Sediment; WBMsed); (2) domain grids for seabed sediment textures (dbSEABED); bathymetry, and channelization; (3) a simulator for ocean dynamics and resuspension (the Regional Ocean Modeling System; ROMS); (4) A simulator (HurriSlip) of seafloor failure and flow ignition; and (5) A Reynolds-averaged Navier–Stokes (RANS) turbidity current model (TURBINS). Model simulations explored physical oceanic conditions that might generate turbidity currents, and allowed the workflow to be tested for a year that included two hurricanes. Results showed that extreme storms were especially effective at delivering sediment from coastal source areas to the deep sea, at timescales that ranged from individual wave events (~hours), to the settling lag of fine sediment (~days).

Numerical modeling of the propagation and morphological changes of turbidity currents using a cost-saving strategy of solution updating

Existing layer-averaged numerical models for turbidity currents have mostly adopted the global minimum time step (GMiTS) for solution updating, which confines their computational efficiency and limits their attractiveness for field applications. This paper presents a highly efficient layer-averaged numerical model for turbidity currents by implementing the combined approach of the local graded-time-step (LGTS) and the global maximum-time-step (GMaTS). The governing equations are solved for unstructured triangular meshes by the shock-capturing finite volume method along with a set of well-balanced evaluations of the numerical flux and geometrical slope source terms. The quantitative accuracy of the model, given reasonably estimated empirical and model parameters (e.g., bed friction, water entrainment, sediment deposition and erosion coefficients), is demonstrated by comparing the numerical solutions against laboratory data of the current front positions and deposition profiles, as well as field data of the current front positions. The improved computational efficiency is demonstrated by comparing the computational cost of the present model against that of a traditional model that uses a GMiTS. For the present simulated cases, the maximum reduction of the computational cost is approximately 80% (e.g., a simulation that cost 1 h before will only require 12 min with the new model).

A 3D Numerical Model for Turbidity Currents

A numerical model that solves two-phase flow motion equations to reproduce turbidity currents that occur in reservoirs, is proposed. Three formalizations of the two-phase flow motion equations are presented: the first one can be adopted for high concentration values; the second one is valid under the hypothesis of diluted concentrations; the third one is based on the assumption that the particles are in translational equilibrium with the fluid flow. The proposed numerical model solves the latter formalization of two-phase flow motion equations, in order to simulate turbidity currents. The motion equations are presented in an integral form in time-dependent curvilinear coordinates, with the vertical coordinate that varies in order to follow the free surface movements. The proposed numerical model is validated against experimental data and is applied to a practical engineering case study of a reservoir, in order to evaluate the possibility of the formation of turbidity currents.

Bayesian assessment of uncertainty in viscosity closure models for turbidity currents computations

Particle-laden flows are complex natural phenomena promoted by the interaction of fluids and solids. A particular class of interest here are turbidity currents. They are one of the mechanisms responsible for sediment transport and deposition that leads to the formation of basins hosting oil reservoirs. Even slight differences in the mixture density induced by the spatial sediment distribution may trigger the turbulent flows capable of carrying heavy loads for long distances. Detailed modeling of turbidity currents may offer new insights to help geologists to understand the deposition mechanisms and the final stratigraphic form of the reservoir. Modeling this complex system is challenging due to the scarcity of observed and measured data, and, also due to the need of employing uncertain and approximate physical hypothesis. One critical source of uncertainty, which is the focus here, is associated with the choice of appropriate phenomenological models for the effective viscosity of the mixture of fluid and sediments. In this context, we employ a Bayesian framework to enable the design of robust computer simulators that take into account parameter uncertainty and model discrepancies. In the present work, we consider a discrepancy model embedded in the viscosity closure model characterized as a random parameter. A hierarchical Bayesian calibration approach is then used to estimate the hyperparameters of the corresponding probability distribution function. We use synthetic data and examine two scenarios, both involving sustained currents inside a channel that mimics laboratory flow conditions. In the first, we use part of the data for calibration and the rest for validating the resulting model. In the second and more challenging one, we change some flow conditions to evaluate the predictive ability of the calibrated computer model.

A two-dimensional layer-averaged numerical model for turbidity currents

AbstractTurbidity currents occur widely in submarine environments, but field-scale numerical simulations of the flow features have not been applied extensively. Here, we present a two-dimensional layer-averaged numerical model to simulate turbidity currents over an erodible sediment bed, and taking into consideration deposition, entrainment and friction. The numerical model was developed based on the open-source code, Basilisk, ensuring well-balanced and positivity-preserving properties. An adaptive spatial discretization was used, which allows multi-level refinement. The adaptive criterion is based on the dynamic features of the flow and sediment concentrations. The numerical scheme has a relatively high computational efficiency compared with models based on the Cartesian mesh. A hypothetical case based on a true large-scale landform (the Moroccan Turbidite System, offshore NW Africa) was studied. Compared with previous models, the current model accounted for the coupling between flow, sediment transportation and bed evolution. This approach may improve simulation results and also allow the simulation of complex field-scale landforms, while preserving the flow details.

How to recognize crescentic bedforms formed by supercritical turbidity currents in the geologic record: Insights from active submarine channels

Submarine channels have been important throughout geologic time for feeding globally significant volumes of sediment from land to the deep sea. Modern observations show that submarine channels can be sculpted by supercritical turbidity currents (seafloor sediment flows) that can generate upstream-migrating bedforms with a crescentic planform. In order to accurately interpret supercritical flows and depositional environments in the geologic record, it is important to be able to recognize the depositional signature of crescentic bedforms. Field geologists commonly link scour fills containing massive sands to crescentic bedforms, whereas models of turbidity currents produce deposits dominated by back-stepping beds. Here we reconcile this apparent contradiction by presenting the most detailed study yet that combines direct flow observations, time-lapse seabed mapping, and sediment cores, thus providing the link from flow process to depositional product. These data were collected within the proximal part of a submarine channel on the Squamish Delta, Canada. We demonstrate that bedform migration initially produces back-stepping beds of sand. However, these back-stepping beds are partially eroded by further bedform migration during subsequent flows, resulting in scour fills containing massive sand. As a result, our observations better match the depositional architecture of upstream-migrating bedforms produced by fluvial models, despite the fact that they formed beneath turbidity currents.

Turbidity Current Dynamics: 1. Model Formulation and Identification of Flow Equilibrium Conditions Resulting From Flow Stripping and Overspill

This study expands the widely used one‐dimensional, four‐equation model for turbidity currents to account for mass, momentum, and energy sinks associated with flow stripping and overspill processes acting upon the turbidity current suspension cloud. The suspension cloud is defined as any portion of the flow extending above the channel levees. The expanded model allows steady turbidity currents to evolve to a uniform, or equilibrium, state where mass, momentum, and energy gained through sediment and clear‐water entrainment processes are balanced by the mass, momentum, and energy lost to flow stripping and overspill. We perform a sensitivity analysis of the expanded model to assess how changes in channel (e.g., slope, channel height, width, bed friction, and radius of curvature) and flow (e.g., sediment grain size, suspension cloud concentration, and turbulence) properties affect the equilibrium flow conditions. By varying the model inputs from half to double their base case values, we find that the equilibrium values can change by up to a factor of 2. We find that the equilibrium conditions, including the flow Richardson number, were generally most sensitive to changes in slope, channel height, grain size, and suspension cloud concentration. Additionally, we identify model parameter space where Richardson subcritical equilibrium flow is possible. The fact that turbidity currents can attain equilibrium, and particularly subcritical equilibrium, might help elucidate the long turbidity current runout distances on low slopes inferred from extensive submarine channel levee systems.

Numerical Modeling of turbidity currents with Ansys CFX and Telemac 3D

Turbidity currents may be a relevant lever to manage the accumulation of fine sediments in reservoirs. In this paper, we propose to show how two different numerical codes simulate the propagation of turbidity currents. Telemac 3D and Ansys CFX 17.1 solver were chosen as they are commonly used by many research and engineering teams. The simulations are performed on two configurations. The first case aims at modeling the plunging of a turbidity current. The second model is validated based on an experimental work performed at EPFL. The latter consisted on testing turbidity current venting as a solution to manage reservoir sedimentation. A long and narrow flume was used to simulate the reservoir where a turbidity current was triggered. The advantages and limits of both approaches are discussed in order to supply guidelines for the modeling of turbidity currents in real reservoirs.

Autogenic influence on the morphology of submarine fans: an approach from 3D physical modelling of turbidity currents

ABSTRACT: Autogenic controls have significant influence on deep-water fans and depositional lobes morphology. In this work, we aim to investigate autogenic controls on the topography and geometry of deep-water fans. The influence of the sediment concentration of turbidity currents on deep-water fans morphology was also investigated. From the repeatability of 3D physical modeling of turbidity currents, two series of ten experiments were made, one of high-density turbidity currents (HDTC) and another of low-density turbidity currents (LDTC). All other input parameters (discharge, sediment volumetric concentration and grain size median) were kept constant. Each deposit was analyzed from qualitative and quantitative approaches and statistical analysis. In each experimental series, the variability of the morphological parameters (length, width, L/W ratio, centroid, area, topography) of the simulated deep-water fans was observed. Depositional evolution of the HDTC fans was more complex, showing four evolutionary steps and characterized by the self-channelizing of the turbidity current, while LDTC fans neither present self-channelizing, nor evolutionary steps. High disparities on the geometrical parameters of the fans, as characterized by the elevated relative standard deviation, suggest that autogenic controls induced a stochastic morphological behaviour on the simulated fans of the two experimental series.

Froude scaling limitations in modeling of turbidity currents

The scaling problem associated with the modeling of turbidity currents has been recognized but is yet to be explored systematically. This paper presents an analysis of the dimensionless governing equations of turbidity currents to investigate the scale effect. Three types of flow conditions are considered: (i) conservative density current; (ii) purely depositional turbidity current; and (iii) mixed erosional/depositional turbidity current. Two controlling dimensionless numbers, the Froude number and the Reynolds number, appear in the non-dimensional governing equations. When densimetric Froude similarity is satisfied, the analysis shows that the results would be scale-invariant for conservative density current under the rough turbulent condition. In the case of purely depositional flows, truly scale-invariant results cannot be obtained, as the Reynolds-mediated scale effects appear in the bottom boundary conditions of the flow velocity and sediment fall velocity. However, the scale effect would be relatively modest. The Reynolds effect becomes more significant for erosional or mixed erosional/depositional turbidity currents as Reynolds-mediated scale effects also appear in the sediment entrainment relation. Numerical simulations have been conducted at three different scales by considering densimetric Froude scaling alone as well as combined densimetric Froude and Reynolds similarity. Simulation results confirm that although the scaling of densimetric Froude number alone can produce scale-invariable results for conservative density currents, variations occur in the case of turbidity currents. The results become scale invariant when densimetric Froude and Reynolds similarities are satisfied simultaneously.

Whole-Process Modeling of Reservoir Turbidity Currents by a Double Layer-Averaged Model

Turbidity current is formed as subaerial open-channel sediment-laden flow plunges into a reservoir. The whole process of reservoir turbidity current, i.e., formation, propagation, and recession, is generally controlled by the water and sediment inputs from upstream and also the reservoir operation scheme specifying the downstream boundary condition. Enhanced understanding of reservoir turbidity current is critical to effective sediment management in alluvial rivers. However, until now there has been a lack of physically based and practically feasible models for resolving the whole process of reservoir turbidity current. This is because the computing cost of three-dimensional modeling is excessively high. Also, single layer-averaged models cannot resolve the formation process characterized by the transition from open-channel sediment-laden flow to subaqueous turbidity current, or the upper clear-water flow as dictated by the operation scheme of the reservoir, which has significant impacts on turbidity current. Here a new two-dimensional double layer-averaged model is proposed to facilitate for the first time whole-process modeling of reservoir turbidity current. The two hyperbolic systems of the governing equations for the two layers are solved separately and synchronously. The model is well balanced because the interlayer interactions are negligible compared with inertia and gravitation, featuring a reasonable balance between the flux gradients and the bed or interface slope source terms and thus applicable to irregular topographies. The model is benchmarked against a spectrum of experimental cases, including turbidity currents attributable to lock-exchange and sustained inflow. It is revealed that an appropriate clear-water outflow is favorable for turbidity current propagation and conducive to improving sediment flushing efficiency. This is significant for optimizing reservoir operation schemes. As applied to turbidity current in the Xiaolangdi Reservoir in the Yellow River, China, the model successfully resolves the whole process from formation to recession. The present work facilitates a viable and promising framework for whole-process modeling of turbidity currents, in support of reservoir sediment management. (C) 2014 American Society of Civil Engineers.

Direct numerical simulations of particle-laden density currents with adaptive, discontinuous finite elements

Abstract. High-resolution direct numerical simulations (DNSs) are an important tool for the detailed analysis of turbidity current dynamics. Models that resolve the vertical structure and turbulence of the flow are typically based upon the Navier–Stokes equations. Two-dimensional simulations are known to produce unrealistic cohesive vortices that are not representative of the real three-dimensional physics. The effect of this phenomena is particularly apparent in the later stages of flow propagation. The ideal solution to this problem is to run the simulation in three dimensions but this is computationally expensive. This paper presents a novel finite-element (FE) DNS turbidity current model that has been built within Fluidity, an open source, general purpose, computational fluid dynamics code. The model is validated through re-creation of a lock release density current at a Grashof number of 5 × 106 in two and three dimensions. Validation of the model considers the flow energy budget, sedimentation rate, head speed, wall normal velocity profiles and the final deposit. Conservation of energy in particular is found to be a good metric for measuring model performance in capturing the range of dynamics on a range of meshes. FE models scale well over many thousands of processors and do not impose restrictions on domain shape, but they are computationally expensive. The use of adaptive mesh optimisation is shown to reduce the required element count by approximately two orders of magnitude in comparison with fixed, uniform mesh simulations. This leads to a substantial reduction in computational cost. The computational savings and flexibility afforded by adaptivity along with the flexibility of FE methods make this model well suited to simulating turbidity currents in complex domains.