TUBES 'Analisa Turbulensi Aliran Fluida padaTiang -Tiang Offshore Hosea Xaverius 0323040023 D4-ME4A

Summary

Averius from class D4 ME 4A presents an analysis of fluid flow turbulence around offshore piles. The study aims to understand the impact of turbulence on cylindrical structures, like those used in marine construction. Through simulations involving three cylinders, the research explores flow dynamics, boundary conditions, and mesh formation to capture turbulence. Results highlight vortex formations, pressure variations, and the behavior of drag and lift coefficients, demonstrating how turbulence influences offshore structures. This study contributes to designing more efficient and resistant offshore structures, offering insights into fluid forces acting on such platforms.

Takeaways

• 😀 Averius presents a major assignment titled *Analysis of Fluid Flow Turbulence on Offshore Piles* to understand fluid flow characteristics around cylindrical structures, such as offshore piles.
• 😀 The simulation model used involves three cylinders representing offshore piles placed in a sea flow domain, with important components being the inlet, outlet, and the surrounding sea domain.
• 😀 The research is crucial for analyzing fluid forces on offshore structures like oil and gas platforms.
• 😀 Boundary conditions were set with fixed velocity at the inlet, relative zero pressure at the outlet, and a no-slip condition on the cylinder walls.
• 😀 The initial conditions assumed the fluid was still or with low initial velocity.
• 😀 Meshing was performed using Salome software, with tetrahedral and hexagonal meshes, refining around the cylinders to capture turbulence details more accurately.
• 😀 OpenFOAM was used to apply boundary conditions and solve the Navier-Stokes equations for simulating fluid flow around the cylinders.
• 😀 The kinematic viscosity value (ν) was set to 0.00813, which influenced the turbulence in the simulated flow.
• 😀 Visualization of fluid vortices shows the intensity of flow disturbances, with strong vortices behind the cylinders indicating dynamic forces acting on the structure.
• 😀 Pressure simulation results show high pressure at the front of the cylinders and low pressure at the back, where the vacuum zone (eddies) occurs, helping understand drag forces on the structure.
• 😀 The drag and lift coefficients fluctuate over time, indicating the presence of vortex shedding and how the flow changes around the cylinders. The third cylinder, located downstream, exhibits more complex flow behavior due to turbulence from the previous cylinders.

Q & A

What is the main goal of the presented research?

The main goal of the research is to analyze fluid flow turbulence around cylindrical structures, specifically offshore piles, to understand the characteristics of turbulence in marine environments and its impact on offshore structures.

Why are offshore piles important in marine structures?

Offshore piles are used as foundations for marine structures, such as oil and gas platforms. Understanding the fluid forces acting on these piles is crucial for the design and stability of such structures in the marine environment.

What simulation domain was used in the study?

The simulation was carried out in a sea flow domain passing through three cylinders that represent offshore piles. The domain includes an inlet on the left, an outlet on the right, and the three cylindrical structures in between.

What boundary conditions were applied in the simulation?

The boundary conditions included a fixed velocity condition at the inlet, a relative zero pressure condition at the outlet, and a no-slip condition at the cylinder walls, meaning the fluid does not move relative to the surface.

What is the purpose of meshing in the simulation?

Meshing divides the simulation domain into small elements to enable numerical solutions. The finer mesh near the cylinders captures turbulence details more accurately, while coarser meshes are used in areas away from turbulence disturbances.

What types of meshes were used in the simulation?

The simulation used both tetrahedral and hexagonal meshes, with refining around the cylinders to ensure higher accuracy in areas with high flow gradients and turbulence.

What software was used for the meshing and simulation?

Meshing was done using Salome software, and the simulation was performed using OpenFOAM, a finite element method-based solver for solving the Navier-Stokes equations.

What initial and simulation parameters were set in OpenFOAM?

In OpenFOAM, the initial time was set to 0, with an end time of 200. The kinematic viscosity (NU) was set to 0.00813, which significantly influences the level of turbulence in the simulated flow.

What do the colors in the vortex visualization represent?

The colors in the vortex visualization represent the intensity of vortices in the fluid flow. These vortices, visible behind the cylinder, indicate flow fluctuations that contribute to dynamic forces on the offshore structure.

How does the drag and lift coefficient vary for the cylinders?

The drag and lift coefficients fluctuate over time due to the turbulent flow. The first two cylinders exhibit oscillating forces, while the third cylinder, positioned downstream, shows more complex and irregular patterns due to the influence of turbulence from the previous two cylinders.

What is the significance of the results obtained in this research?

The results are valuable for designing more efficient and resilient offshore structures by understanding how turbulent flow interacts with multiple cylindrical structures, which helps in predicting fluid forces and improving structural stability.