Low-density Flow Research Articles

When does Reckless Driving Occurs? Case Study in Nampula, Mozambique

This study investigates the influence of traffic conditions on reckless driving behavior in Nampula, Mozambique, where road accidents claim several lives daily. Previous research has largely focused on individual driving behaviors, neglecting the impact of traffic environments on such behaviors. This study addresses this gap by categorizing vehicles into four groups: passenger cars, minibuses, trucks, and motorcycles, and classifying traffic conditions using k-means clustering. Three distinct traffic patterns were identified: Motorcycle and Car Dominant Traffic (MCDT), High-Density Traffic Flow (HDTf), and Low-Density Traffic Flow (LDTf). Results show that reckless driving is significantly influenced by traffic conditions, with minibuses, motorcycles, and trucks being key contributors. Pattern 2 (HDTf) demonstrated the highest occurrence of reckless driving, driven by competition among minibus drivers, the obstructive presence of trucks, and risky motorcycle maneuvers. Pattern 1 also exhibited elevated risk, particularly performed among motorcycle riders, while Pattern 3 (LDTf) showed the lowest risk due to reduced traffic density. Poisson regression analysis revealed that increased traffic flow in any vehicle category is associated with higher rates of reckless driving. Minibuses and motorcycles, functioning as demand-oriented public transport, engage in competitive and unsafe behaviors, while trucks, though not engaging in reckless driving directly, act as barriers that exacerbate risky maneuvers by other vehicles. These findings highlight the need for dedicated lanes for minibuses and motorcycles and tailored traffic safety policies to mitigate reckless driving.

Comprehensive Evaluation of the Massively Parallel Direct Simulation Monte Carlo Kernel “Stochastic Parallel Rarefied-Gas Time-Accurate Analyzer” in Rarefied Hypersonic Flows—Part A: Fundamentals

The Direct Simulation Monte Carlo (DSMC) method, introduced by Graeme Bird over five decades ago, has become a crucial statistical particle-based technique for simulating low-density gas flows. Its widespread acceptance stems from rigorous validation against experimental data. This study focuses on four validation test cases known for their complex shock–boundary and shock–shock interactions: (a) a flat plate in hypersonic flow, (b) a Mach 20.2 flow over a 70-degree interplanetary probe, (c) a hypersonic flow around a flared cylinder, and (d) a hypersonic flow around a biconic. Part A of this paper covers the first two cases, while Part B will discuss the remaining cases. These scenarios have been extensively used by researchers to validate prominent parallel DSMC solvers, due to the challenging nature of the flow features involved. The validation requires meticulous selection of simulation parameters, including particle count, grid density, and time steps. This work evaluates the SPARTA (Stochastic Parallel Rarefied-gas Time-Accurate Analyzer) kernel’s accuracy against these test cases, highlighting its parallel processing capability via domain decomposition and MPI communication. This method promises substantial improvements in computational efficiency and accuracy for complex hypersonic vehicle simulations.

The preparation technology and catalytic mechanism of PVDF/PVP/a-MoSx porous membrane for water flow driven piezoelectric PMS activation

Piezoelectric catalysis couples with peroxymonosulfate (PMS) activation technology can efficiently increase the yield of reactive oxygen species (ROS). Herein, a novel flexible polyvinylidene difluoride/polyvinyl pyrrolidone/amorphous molybdenum sulfide (PVDF/PVP/a-MoSx) membrane with finger-like pore structure was prepared by non-solvent induced phase separation (NIPS) method. As a result, a-MoSx nanosheets can be exposed out of the pores to provide multiple active sites. The PVDF/PVP/a-MoSx with large dipole moment can form enhanced polarization field under water flow to accelerate the charges separation and transfer, thereby promoting the breakage of the OO bond of PMS. The mechanism of piezo-photocatalytic activated PMS was confirmed by COMSOL multiphysics simulations, electrochemical experiments, contribution of active species and DFT calculations. Moreover, a self-cycling degradation reactor was proved more effective in generating piezoelectric potential and improving the degradation efficiency, supporting the practical potential of this strategy. This study provides a new platform to develop piezoelectric porous membrane for enhanced PMS activation under low density flow water energy.

Measurements of Turbulence in Compressible Low-Density Flows at the Inlet of a Transonic Linear Cascade With and Without Unsteady Wakes

Abstract In the present work, hot-wire anemometry was employed for the characterization of the turbulent field at the inlet of a high-speed low-pressure turbine cascade, in terms of turbulence intensity and integral length scales. This work addresses two major topics relevant to the turbomachinery field: the application of hot-wire anemometry in transonic and rarefied flow regimes and the decoupling of the deterministic and the stochastic fluctuations when measuring unsteady phenomena. In compressible and rarefied flows, a hot-wire is strongly sensitive to both density and velocity fluctuations, and the commonly used Nusselt–Reynolds correlations are not valid. In this article, a nondimensional calibration methodology, based on Nusselt, Reynolds, and Knudsen numbers, was coupled with a sensitivity analysis and employed to postprocess the experimental dataset, allowing to decouple the fluctuations of density and velocity and to compute the turbulence parameters. In the presence of unsteady wakes generated upstream of the cascade, two different phase-locked averaging techniques were employed to distinguish the wake deterministic fluctuations from the background turbulence intensity.

Topology optimization for flow machine rotor design considering resonance and low mass density flows

When designing structures that take part in rotating fluid flow machines, one important effect that may be taken into account is resonance, which is evaluated through the modal analysis. Under rotating conditions, the formulation and behavior of the structure changes, requiring a new formulation. Thus, this work formulates the fluid flow topology optimization for rotating resonance, while also considering a low mass density (compressible or incompressible) fluid flow. Therefore, three different effects are considered in the fluid flow-based design: from the modal analysis, from the solid structure, and from the low mass density fluid flow. The topology optimization problem is formulated for a simplified 2D model of a rotating fluid flow device, and a nodal design variable. The topology optimization is performed through an integer linear programming algorithm. Numerical examples are presented for the developed topology optimization formulation.

A platoon-based eco-driving control mechanism for low-density traffic flow

Forming traffic into platoons on the road has the potential for mitigation of traffic congestion and improvement in fuel economy, and can be more readily achieved by leveraging emerging connected and automated vehicles. This paper proposes a platoon-based eco-driving control mechanism that forms small-sized platoons and guides them to move on low-density traffic corridors. To facilitate this investigation, a low-density traffic corridor is divided into an initial road segment plus a series of subsequent road segments. To ensure computational efficiency, an approximate model based on the predefined function is employed. Simulation shows that traffic flow of small-sized platoons can bring considerable benefits in fuel consumption compared to that of large-sized platoons. This proposed control mechanism is shown to be significant in fuel economy.

Experimental measurement of the pressure drop and heat transfer characteristics of a crossflow heat exchanger in low-density flows

NASA and other space agencies are currently planning the first human missions to Mars in the next 20 years. These missions will require much more power than current robotic missions, and so will require significant waste heat rejection capabilities to maintain steady state operations. Forced convection heat exchangers, particularly crossflow tube array compact heat exchangers, may offer significant volume- and mass-efficiency benefits over radiators for these applications. However, no experimentally validated correlations exist in the literature for the pressure drop and heat transfer characteristics of a forced-convection heat exchanger under the relevant dimensionless conditions which correspond to low (7-200) Reynolds number and moderate (0.0009-0.009) Knudsen number under axial and vortical flows. A staggered-tube crossflow heat exchanger has been constructed and its performance experimentally measured in a low-density wind tunnel. Data has been gathered in low-Reynolds, moderate-Knudsen conditions for both axial and vortical flows over a range of pressures and wall temperatures that is relevant to future Mars or high-altitude heat exchanger operation using both CO2 and air. The measured pressure drop exceeds what is predicted by correlations in the literature at very low (<75) Reynolds number while the Nusselt numbers were fairly well-predicted by existing correlations. A new correlation for pressure drop is presented for low-Reynolds, axial and vortical flow through a staggered circular tube array in crossflow.

Numerical investigation of heat transfer and pressure drop characteristics on the hot fluid side of the plate-fin precooler under negative pressure conditions

Plate-fin heat exchangers are widely employed in aerospace and many other fields due to the advantage of high efficiency and low resistance. However, they usually operate at atmospheric or high-pressure conditions. In this study, The commercial CFD solver Fluent 16.0 was used to evaluate the overall performance of the plate-fin precooler whose hot fluid is nitrogen under negative pressure and high temperature conditions. The characteristics of the hot fluid flow field inside the precooler with and without fins were investigated. The effect of fin number on the heat transfer and pressure drop characteristics of the hot fluid side was analyzed. Furthermore, the comprehensive performance of the precooler under different pressure conditions was compared quantitatively. The results showed that under negative pressure conditions, the hot fluid flow field features inside the precooler without fins was regular, while that of the precooler with fins took on a “<” shaped flow features, indicating the evolving of thermal boundary layer. It was also found that the comprehensive performance of the precooler did not increase with an increase in the number of fins when the hot fluid was in a low-density and high-speed flow state. Moreover, pressure conditions did not affect the heat transfer performance of the precooler but had a significant impact on the pressure drop performance.

Toward a 3D physical model of diffusive polymer chains.

Recent studies in polymer physics have created macro-scale analogs to solute microscopic polymer chains like DNA by inducing diffusive motion on a chain of beads. These bead chains have persistence lengths of O(10) links and undergo diffusive motion under random fluctuations like vibration. We present a bead chain model within a new stochastic forcing system: an air fluidizing bed of granular media. A chain of spherical 6 mm resin beads crimped onto silk thread are buffeted randomly by the multiphase flow of grains and low density rising air "bubbles". We "thermalize" bead chains of various lengths at different fluidizing airflow rates, while X-ray imaging captures a projection of the chains' dynamics within the media. With modern 3D printing techniques, we can better represent complex polymers by geometrically varying bead connections and their relative strength, e.g., mimicking the variable stiffness between adjacent nucleotide pairs of DNA. We also develop Discrete Element Method (DEM) simulations to study the 3D motion of the bead chain, where the bead chain is represented by simulated spherical particles connected by linear and angular spring-like bonds. In experiment, we find that the velocity distributions of the beads follow exponential distributions rather than the Gaussian distributions expected from polymers in solution. Through use of the DEM simulation, we find that this difference can likely be attributed to the distributions of the forces imparted onto the chain from the fluidized bed environment. We anticipate expanding this study in the future to explore a wide range of chain composition and confinement geometry, which will provide insights into the physics of large biopolymers.

Dominance of Phycosiphon incertum vs Zoophycos in shelf environment: example from the transgressive Palermo Aike black shale deposits of the Austral-Magallanes Basin, Argentina

The Zoophycos ichnofacies and its main components, Zoophycos isp., Phycosiphon incertum and Chondrites isp. have been related to marine environments of low energy and oxygen. This situation is very common in shelf environments of the past, the most important oil source rocks and/or unconventional reservoir. The Early Cretaceous Palermo Aike Formation of the Austral-Magallanes Basin (Southern Argentina) records marine sedimentation, composed mainly by black shales, with subordinate fine-grained sandstones, and redeposited tuff, deposited in a shelf environment. This succession is the main source rock and constitute a latent unconventional reservoir of the basin. In this paper we present the sedimentological and ichnological study of two well cores from the Tierra del Fuego area. These cores record the initial stage of the marine transgression, and the development of a distal shelf environment, with an alternation of black shales and, fine-grained tuff sandstones hyperpycnal deposits. The ichnological content that records this transgression shows three different ichnofacies: i) autochthonous Cruziana ichnofacies represented by Thalassinoides isp., Teichichnus isp., Planolites isp., Chondrites isp. and Rizocorallium isp. This trace fossil association is rapidly replaced by ii) Zoophycos ichnofacies represented by Phycosiphon incertum, Chondrites isp., and small Zoophycos isp. Finally, another allochthonous Cruziana ichofacies is observed related to the low-density turbiditic deposits, composed by Thalassinoides isp., Gyrolithes, Teichichnus isp., Scolicia isp. and Haenzchellinia isp. In the Santa Cruz area, a large Zoophycos isp. dominance is observed in the fine-grained deposits, occasionally interbedded with coarser-grained low-density turbiditic deposits with doomed pioneers. In the study area (Tierra del Fuego), on the contrary, a dominance of Phycosiphon incertum is observed instead of Zoophycos isp. which when is present have very poor development in size. This could be due to the fact that low-density turbiditic flows are very frequent in the study area, which generates a very unstable environment that does not allow the development of large Zoophycos isp. This environmental differences between the outcrops of Santa Cruz in the north of the basin and the subsurface study area in Tierra del Fuego may be triggered due to climatic, volcanic, or tectonic allogenic control factors.

A numerical investigation of pedestrian dynamics based on rational behaviour in different density scenarios

In this work, we extend a microscopic rational behaviour pedestrian model and investigate it and the related macroscopic model numerically. A coupling with an eikonal equation is performed to include more complex geometries and pedestrian behaviour. We compare the microscopic and macroscopic models to classical social force type models. We observe that the more complex rational behaviour approach gives physically more reasonable results in low-density cases. However, in higher density scenarios, an additional social force type term is required to avoid nonphysical overcrowding. We present numerical experiments and a numerical comparison with social force type models for a variety of different physical scenarios, including low and high density situations and flow problems with and without obstacles. The numerical simulations are realised by solving the model equations in a Lagrangian form using a mesh-free particle method. In this numerical context, the model is easily extended, for example, to moving obstacle scenarios, as presented in a final example.

Heterogenous morphogenesis of Caco-2 cells reveals that flow induces three-dimensional growth and maturation at high initial seeding cell densities.

Here, we introduce a customized hanging insert fitting a six-well plate to culture Caco-2 cells on hydrogel membranes under flow conditions. The cells are cultured in the apical channel-like chamber, which provides about 1.3 dyn/cm2 shear, while the basolateral chamber is mixed when the device is rocked. The device was tested by investigating the functional impact of the initial seeding density in combination with flow applied at confluency. The low seeding density cultures grew in two dimensional (2D) irrespective of the flow. Flow and higher seeding density resulted in a mixture of three dimensional(3D) structures and 2D layers. Static culture and high cell seeding density resulted in 2D layers. The flow increased the height and ZO-1 expression of cells in 2D layers, which correlated with an improved barrier function. Cultures with 3D structures had higher ZO-1 expression than 2D cultures, but this did not correlate with an increased barrier function. 2D monolayers in static and dynamic cultures had similar morphology and heterogeneity in the expression of Mucin-2 and Villin, while the 3D structures had generally higher expression of these markers. The result shows that the cell density and flow determine 3D growth and that the highest barrier function was obtained with low-density cultures and flow.

Towards higher efficiency and less consumption: Control Strategy and Simulation for CAV platooning

Platooning is the application of autonomous driving technology to provide a freight transportation solution. It can improve the efficiency of freight transportation, save energy and reduce consumption, which are the major concerns of freight transportation. Configuration strategies are sets of rules for vehicles joining a platoon. Two types of configuration strategies are proposed in this paper, namely fixed platoon configuration strategies (Fixed-PCS) and flexible platoon configuration strategies (Flexible-PCS). In order to verify the impact of these strategies on freight efficiency and energy reductions, an energy consumption model is designed and performed. A discussion about the maximum platoon length and a design of platoon configuration strategies in connected and autonomous driving scenarios are presented. For freight vehicles, an agent-based simulation model is established, in which the efficiency and consumption evaluation indicators are used to measure the platooning effect under different traffic densities. The results show that in low-density traffic flow, the application of Flexible-PCS can improve the average speed on freeway in addition to reducing the average number of lane changes. The relationship between platoon length and energy consumption at different traffic flow densities are plotted, and recommendations on the optimal platoon lengths under different traffic flow densities are proposed.

Mechanism of formation and Characteristics of deposition of Cambrian gravity flow in the eastern gucheng area, Tarim Basin

The Gucheng Cambrian margin and Luoxi Cambrian margin is on both sides of eastern Tarim basin. Base on the analysis of cores,thin sections and seismic data of Luoxi slope areas,this paper systematically studies the formation condition, reservoir characteristics and favorable accumulation factors of gravity flow. The gravity flow sedimentary types include debris flow, high density flow and low density flow, debris flow and high density flow reservoir is better. Hydrothermal reconstruction has active effect on reservoir. There are six phases mound-beaches develop in platform margin, reservoir characteristics are algae framework dolomite and granular dolomite. Phases of mound-beaches develop to steep slope. Seismic and geochemical data indicate that the mound-beaches are exposed with corrosion characteristics,the platform margin-slope have the requirements of geomorphologie antique and quality reservoir source.

Positivity-preserving high order finite difference WENO schemes for compressible Navier-Stokes equations

In this paper, we construct a high order weighted essentially non-oscillatory (WENO) finite difference discretization for compressible Navier-Stokes (NS) equations, which is rendered positivity-preserving of density and internal energy by a positivity-preserving flux splitting and a scaling positivity-preserving limiter. The novelty of this paper is WENO reconstruction performed on variables from a positivity-preserving convection diffusion flux splitting, which is different from conventional WENO schemes solving compressible NS equations. The core advantages of our proposed method are robustness and efficiency, which especially are suitable for solving tough demanding problems of both compressible Euler and NS equation including low density and low pressure flow regime. Moreover, in terms of computational cost, it is more efficient and easier to implement and extend to multi-dimensional problems than the positivity-preserving high order discontinuous Galerkin schemes and finite volume WENO scheme for solving compressible NS equations on rectangle domain. Benchmark tests demonstrate that the proposed positivity-preserving WENO schemes are high order accuracy, efficient and robust without excessive artificial viscosity for demanding problems involving with low density, low pressure, and fine structure.

Correlation between waverider shock waves and aerodynamic forces in supersonic rarefied flow, experimental investigation in the wind tunnel MARHy

This paper presents an experimental study of the influence of viscous flows on the aerodynamic behaviour of waveriders. This investigation was carried out in the MARHy facility, under supersonic and rarefied flow conditions. Three supersonic and low density flow conditions were tested operating at Mach 2 and 4 with free stream pressures of 8 Pa and 2.67 Pa giving slip regime flows. Knudsen numbers associated with these flow conditions and this test model are between 2.79 × 10-3 and 7.33 × 10-4. In terms of pressure, these conditions are similar at altitudes between 50 km and 80 km. The studied waverider has a geometry proposed in the literature and optimised for a Mach 10 flow and an altitude of 50 km. The purpose of this work is to experimentally analyse how viscous effects will affect the aerodynamic performances of the waverider in off-design conditions. This work is based on the analysis of the upper and lower shock wave angles obtained from glow discharge imaging technique for different angles of attack and the three operating conditions. Results showed that the evolution of shock wave angles are Mach number dependent, as predicted by the inviscid shock relations, but also strongly depends on the flow pressure. From these experimental results, fitting equations have been established to predict the variation of upper and lower shock angles with the flow density, Mach number as a function of the angle of attack in continuum and especially in slip regime. Shock wave angles behaviour are compared to measured Lift-to-Drag ratio. Comparison presents a similar behaviour with flows conditions and shows that viscous layers appearing at low densities have a great influence on aerodynamic forces.

Numerical analysis of deflection control of a gas plasma jet based on magnetohydrodynamic staggered electrode configuration

To control the deflection of the gas plasma jet, a new analytical method is proposed based on the Magnetohydrodynamic (MHD) technique. Based on the typical MHD power generation model, the applied voltage is applied to the staggered electrodes, that is, a pair of electrodes on the same side wall are connected to generate an axial current in the channel. Under the action of the magnetic field perpendicular to the direction of the flow, the plasma is subjected to electromagnetic forces perpendicular to these two directions, and the jet is deflected. The computational model including the Navier-Stokes equations coupled with electromagnetic source terms, the electric potential equation and Ohm’s law is solved. The deflection of the gas jet under the action of an electromagnetic field is observed, and the maximum deflection angle is about 14.8°. The influences of the electric field, magnetic field, and conductivity on the jet deflection are studied. Results show that although the influences of these three factors on the deflection are similar, and the effect of increasing the electric field strength is slightly greater, priority should be given to increasing the magnetic field strength from the perspective of reducing energy consumption. The Stuart number is introduced to assess the ability of electromagnetic force to control jet deflection. When the electromagnetic parameters are constant, this solution provides better control of low-density and low-speed fluid flows. The calculation results show that using the staggered electrode method configuration is feasible in terms of controlling the deflection of a plasma jet deflection.

Different types of gravity-driven flow deposits and associated bedforms in the Upper Bengal Fan, offshore Myanmar

This study uses 3D reflection seismic data to investigate how sediment gravity flows contribute to the evolution of the lower continental slope of the Myanmar margin that is part of the Bengal Fan, the largest deep-water fan system in the world. Seafloor and subseafloor data show large sediment wave fields that developed on both flanks of an extensive submarine canyon. The sediment waves exhibit asymmetric stoss and lee sides, wave lengths and heights of 850–3000 m and 25–70 m, respectively, and an upslope direction of migration. Seismic data reveals the presence of multiple fields of vertically stacked sediment waves, interbedded with units characterised by a chaotic seismic facies that accumulate mainly in the troughs of the sediment waves and can be tracked laterally to the adjacent canyons. According to their seismic facies, geometry, and internal architecture these chaotic units are interpreted as debrites. Seismic attributes extracted from different horizons indicate that the sediment waves are dominated by fine-grained sediment, while the debrites are probably associated with coarser-grained deposits. The debrites fill the troughs of the sediment waves, as well as the downstream portions of canyon thalweg, thus flattening the paleo-seafloor. The sediment waves are interpreted as cyclic steps formed by low-density turbidity currents flowing across the slope down to the basin floor, where the change in gradient favours the formation of hydraulic jumps and the transition from supercritical to subcritical flow conditions. A conceptual model for the sediment wave evolution was proposed for the study area, in the transitional environment on the lower slope, with low-density gravity flow deposits and high-density debris flow deposits alternatively accumulating on the major gravity flow conduits.

Separation performance of hydrocyclones with medium rearrangement internals

The inlet section of hydrocyclone has a significant effect on separation efficiency. However, in most existing studies the inlet of conventional hydrocyclones (CH) only serves as a channel for the mixed liquid to enter the hydrocyclone body. Based on CH's tangential inlet with a rectangular section, a novel hydrocyclone with medium rearrangement internals (HMRI) was designed and the rearrangement internals (RIs) were installed inside the inlets. The RIs include one separating block and 3 division plates following the block. Thus, the rearrangement of immiscible media can be achieved after passing through this inlet, i.e., media with different densities flow into different layers. Most of the rearranged low-density phase flows directly into the central area of HMRI. Meanwhile, most of high-density phase flows to the wall zone, which is beneficial for the subsequent centrifugal separation process in HMRI’s body. Taking the oil-water mixture as the example, three kinds of separating blocks, semi-cylindrical block (SCB), triangular prism block (TPB), and trapezoidal body block (TBB) were designed and compared to no-block cases (conventional inlet) through simulations. Results showed that RIs with SCB displayed excellent rearrangement effect as well as a low pressure drop. Additionally, the comparison between CH and HMRI was conducted via oil-phase distribution, velocity distribution, and separation efficiency. Our results show that the separation efficiency of the novel HMRI was 6.4–8.0% higher than the traditional CH, under various operating conditions. The application potential of HMRI in biological processes for wastewater treatment was also analysed and discussed.

Deformation–sedimentation feedback and the development of anomalously thick aggradational turbidite lobes: Outcrop and subsurface examples from the Hikurangi Margin, New Zealand

ABSTRACT Concepts of the interaction between autogenic (e.g., flow process) and allogenic (e.g., tectonics) controls on sedimentation have advanced to a state that allows the controlling forces to be distinguished. Here we examine outcropping and subsurface Neogene deep-marine clastic systems that traversed the Hikurangi subduction margin via thrust-bounded trench-slope basins, providing an opportunity to examine the interplay of structural deformation and deep-marine sedimentation. Sedimentary logging and mapping of Miocene outcrops from the exhumed portion of the subduction wedge record heavily amalgamated, sand-rich lobe complexes, up to 200 m thick, which accumulated behind NE–SW-oriented growth structures. There was no significant deposition from low-density parts of the gravity flows in the basin center, although lateral fringes demonstrate fining and thinning indicative of deposits from low-density flows. Seismic data from the offshore portion of the margin show analogous lobate reflector geometries. These deposits accumulate into complexes up to 5 km wide, 8 km long, and 300 m thick, comparable in scale with the outcropping lobes on this margin. Mapping reveals lobe complexes that are vertically stacked behind thrusts. These results illustrate repeated trapping of the sandier parts of turbidity currents to form aggradational lobe complexes, with the finer-grained suspended load bypassing to areas downstream. However, the repeated development of lobes characterized by partial bypass implies that a feedback mechanism operates to perpetuate a partial confinement condition, via rejuvenation of accommodation. The mechanism proposed is a coupling of sediment loading and deformation rate, such that load-driven subsidence focuses stress on basin-bounding faults and perpetuates generation of accommodation in the basin, hence modulating tectonic forcing. Recognition of such a mechanism has implications for understanding the tectono-stratigraphic evolution of deep-marine fold and thrust belts and the distribution of resources within them.