A Turbidity Current Flow CFD simulation is essential for understanding the ocean floor. Turbidity currents are like underwater avalanches. They are mixtures of water and sand that flow down slopes due to gravity. These powerful flows can damage underwater cables and pipelines. Therefore, engineers use Turbidity Current Flow Fluent simulations to predict their path and strength without expensive deep-sea tests.

In this report, we use Granular ANSYS Fluent tools to model the complex interaction between the fluid and the solid particles. We specifically use the Eulerian multiphase fluent model. This method allows us to treat the sand not just as a fluid, but as a “granular phase” with real physical collisions. This Turbidity Current Flow CFD simulation helps geologists and engineers see how sediment settles and spreads. It provides critical data for designing safer offshore structures. For more details on simulating particle flows, please explore our Multiphase tutorials: https://cfdland.com/product-category/module/multiphase-cfd-simulation/

• Reference [1]: Baas, Jaco H., Wessel Van Kesteren, and George Postma. “Deposits of depletive high‐density turbidity currents: a flume analogue of bed geometry, structure and texture.” Sedimentology5 (2004): 1053-1088.
• Reference [2]: Georgoulas, Anastasios N., et al. “Numerical investigation of continuous, high density turbidity currents response, in the variation of fundamental flow controlling parameters.” Computers & Fluids60 (2012): 21-35.

Figure 1: A 3D schematic showing the slope and basin geometry used for the Turbidity Current Flow CFD simulation [2].

Simulation Process: Eulerian Granular Model and Mesh Setup

The simulation process for this Turbidity Current Flow CFD project began with a high-quality mesh generation. We used ICEM software to build a structured grid with 1,414,820 cells. We chose hexahedral (cube-shaped) cells because they are very accurate for flows that move along a flat bottom. This precise grid is necessary for the Granular ANSYS Fluent solver to calculate exactly where the sand goes.

Inside ANSYS Fluent, the physics setup relied on the Eulerian multiphase fluent model. This is the most advanced way to simulate dense particle flows. We defined two phases: water (liquid) and sediment (granular solid). A key part of the setup was defining the Granular phase Fluent properties. We input real experimental data for particle diameter, density, and “restitution coefficient” (how much particles bounce). This model calculates not just the flow of water, but also the friction and collisions between sand grains. This detailed setup allows the Turbidity Current Flow Fluent simulation to replicate the real physics of underwater sediment transport.

Figure 2: A 2D diagram of the computational domain, illustrating the inlet channel and the expansion tank area.

Figure 3: The structured computational grid with 1,414,820 hexahedral cells, designed to capture the flow near the seabed.

Post-processing: Sediment Deposition and Velocity Analysis

The post-processing analysis provides a deep look into the mechanics of the flow. We must examine the contours and graphs to understand the danger and behavior of these currents. First, we analyze the Volume Fraction contours in Figure 4. The red color represents a very high concentration of sand, up to 51% volume fraction. The simulation reveals a critical phenomenon: the “head” of the current is the densest and heaviest part. As time moves from T1 to T2, we see the red zone shrinking and turning green (around 15%). This proves that the Turbidity Current Flow CFD simulation correctly captures the “deposition process.” The current loses energy, and the heavy sand falls out of the water. For an engineer designing a pipeline, this is vital. It shows exactly where the heavy sediment pile-up will occur. Next, we look at the physics of speed using the graph in Figure 6. The red line represents the flow inside the narrow channel. Here, the velocity hits a peak of 0.75 m/s. This is the most destructive phase where erosion can happen. However, the green line (tank velocity) is much lower. This confirms that as the flow expands, it spreads out and slows down rapidly.

Figure 4: Volume Fraction contours at times T1 and T2, visualizing the high sediment concentration diluting as the flow travels.

Figure 5: A 3D visualization from ANSYS Fluent showing the turbidity current exiting the narrow channel and spreading into the open tank.

Finally, the 3D view in Figure 5 ties everything together. It shows the lateral spreading of the flow. The current does not just go straight; it fans out. This visual evidence from Granular ANSYS Fluent is essential for “hazard assessment.” It tells manufacturers that they cannot just protect the area directly in front of a canyon; they must also protect a wide area on the sides. The simulation successfully links the high speed in the channel to the sediment settling in the basin, providing a complete picture of the event.

Figure 6: A graph of Velocity vs. Time at three locations, confirming the rapid deceleration of the Turbidity Current Flow as it expands.