Mining of Deep-Seabed Nodules Using a Coandă-Effect-Based Collector

We present an effective design of a hydraulic, polymetallic nodule collector, which fundamentally depends on the Coandă effect in harvesting nodules. The design was first developed based on 2D numerical simulations conducted using a computational fluid dynamics tool, ANSYS FLUENT. Following that, the design was tested in full-scale experiments,...

Sediment Erosion Generated by a Coandă-Effect-Based Polymetallic-Nodule Collector

To date, hydraulic collection is the most widely considered technology in polymetallic-nodule mining, since there is no direct contact between hydraulic collectors and ocean floor. To construct a hydraulic collector that results in the least sediment disturbance, it is critical to develop an insightful understanding of the interaction between...

Stabilizing and Destabilizing Breaching Flow Slides

As a result of the dilation of soil matrix, dense submarine sand slopes can temporarily be steeper than the natural angle of repose. These slopes gradually fail by the detachment of individual grains and intermittent collapses of small coherent sand wedges. The key question is whether steep disturbances in a submarine slope grow in size ...

3D CFD Study of Scour in Combined Wave–Current Flows around Rectangular Piles with Varying Aspect Ratios

This study utilizes three-dimensional simulations to investigate scour in combined wave–current flows around rectangular piles with various aspect ratios. The simulation model solves the Reynolds-averaged Navier–Stokes (RANS) equations using the k–ω turbulence model, and couples the Exner equation to compute bed elevation changes. The model also...

Full-scale experiments on a coandă-effect-based polymetallic-nodule collector

Polymetallic nodules are potato-sized rock accretions that form on vast areas of the abyssal plains of the global ocean. These nodules are rich in commercially precious metals, such as nickel, cobalt and copper, making them a target for potential future deep-sea exploitation. Generally, polymetallic nodules are partially buried in the seabed...

Experimental investigation of sediment erosion generated by a coandă-effect-based polymetallic-nodule collector

Owing to the absence of direct contact between hydraulic polymetallic-nodule collectors and seabed, hydraulic collection is deemed, from an environmental point of view, the most preferred technique in nodule mining. To design a hydraulic collector that results in minimum sediment disturbance, it is crucial to develop a solid understanding of the...

Breaching Flow Slides and the Associated Turbidity Currents: Large-Scale Experiments and 3D Numerical Modelling

Underwater slope failure is a common problem in the fields of geotechnical, dredging and hydraulic engineering, posing a major risk to submerged infrastructure and flood defences along coasts, rivers, and lakes. The term ‘flow slide’ refers to a specific, complex failure mechanism of underwater slopes, which occurs when a substantial amount of...

Near-Field Analysis of Turbidity Flows Generated by Polymetallic Nodule Mining Tools

The interest in polymetallic nodule mining has considerably increased in the last few decades. This has been largely driven by population growth and the need to move towards a green future, which requires strategic raw materials. Deep-Sea Mining (DSM) is a potential source of such key materials. While harvesting the ore from the deep sea by a...

Preliminary Evaluation of Existing Breaching Erosion Models

The ability to estimate the erosion rate along an underwater breach face is crucial to understand the evolution of breaching failure. To this end, breaching erosion models were developed and applied in numerical models. However, these erosion models have never been validated, owing to the scarcity of direct measurements of turbidity currents...

Modeling of Breaching-Generated Turbidity Currents Using Large Eddy Simulation

Breaching flow slides result in a turbidity current running over and directly interacting with the eroding, submarine slope surface, thereby promoting further sediment erosion. The investigation and understanding of this current are crucial, as it is the main parameter influencing the failure evolution and fate of sediment during the breaching...

Breaching Flow Slides and the Associated Turbidity Current

This paper starts with surveying the state-of-the-art knowledge of breaching flow slides, with an emphasis on the relevant fluid mechanics. The governing physical processes of breaching flow slides are explained. The paper highlights the important roles of the associated turbidity current and the frequent surficial slides in increasing the...

Large-scale Experiments on Breaching Flow Slides and the Associated Turbidity Current

Breaching flow slides are accompanied by the generation of turbidity currents. Measurements of these currents are critical for understanding the interaction between the turbidity current and the slope surface, as well as for the validation of numerical models. However, there are insufficient data available detailing the velocity distribution or...

The need for experimental studies on breaching flow slides

Recent studies have revealed that breaching, rather than liquefaction, is the dominant failure process in underwater slopes of fine sand and the main driver of observed flow slides in nature. As a result, breaching is getting more attention from hydraulic and geotechnical researchers. Measurements of breaching-generated turbidity currents are...