Related Experiment Video
Updated: Mar 6, 2026
09:58
Investigating the Three-dimensional Flow Separation Induced by a Model Vocal Fold Polyp
Published on: February 3, 2014
8.9K
Modelling turbulent boundary layer flow over fractal-like multiscale terrain using large-eddy simulations and
1Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA xiangyang@jhu.edu.
Summary
This study introduces a dynamic model for subgrid-scale roughness in large-eddy simulations (LES) of wind turbines on complex terrain. The model provides resolution-independent results for mean velocity, improving wind energy predictions.
Area of Science:
- Fluid dynamics
- Atmospheric boundary layer modeling
- Renewable energy systems
Background:
- Complex terrain and surface roughness significantly impact wind turbine performance.
- Current large-eddy simulations (LES) struggle to resolve small-scale terrain features, necessitating subgrid-scale models.
- Accurate modeling of ground surface effects is crucial for wind farm design.
Purpose of the Study:
- To develop and validate a dynamic approach for subgrid-scale roughness parametrization in LES.
- To investigate the flow response to multi-scale roughness elements.
- To improve the accuracy of wind energy predictions in complex terrains.
Main Methods:
- Adaptation of a dynamic approach for subgrid-scale roughness parametrization.
- Application to rough surfaces with broad size distributions of cuboidal elements.
- Development of an analytical roughness model incorporating sheltering and shading effects.
Main Results:
- The dynamic roughness model yields resolution-independent mean velocity distributions in LES.
- The analytical roughness model, considering shading and conservation laws, shows good agreement with LES-derived parameters.
- The study demonstrates effective modeling of flow over rough surfaces with multiple scales.
Conclusions:
- The developed dynamic and analytical roughness models enhance LES accuracy for wind turbines on complex terrain.
- These models provide a robust method for accounting for unresolved surface roughness.
- Improved modeling contributes to more reliable wind energy assessments in challenging environments.
More Related Videos
Related Concept Videos
01:18Boundary Layer Characteristics
737
When a fluid encounters a solid surface, a boundary layer forms due to the interaction between the fluid's motion and the stationary surface. This phenomenon is characterized by a thin region adjacent to the surface where viscous forces dominate, influencing the fluid's velocity profile. The development of the boundary layer begins at the leading edge of the surface and evolves as the fluid moves downstream.As the fluid flows over the surface, friction between the fluid and the wall slows down...
737
01:30Typical Model Studies
665
Fluid mechanics model studies often utilize scaled-down systems to predict fluid behavior in full-scale environments, such as river flows, dam spillways, and structures interacting with open surfaces. Maintaining Froude number similarity in river models is crucial, as it replicates surface flow features like wave patterns and velocities.
665
01:24Turbulent Flow
819
Turbulent flow is characterized by unpredictable fluctuations in velocity and pressure, which result in a chaotic fluid movement distinct from the orderly patterns of laminar flow. While laminar flow is governed by smooth, parallel layers with minimal mixing, turbulent flow exhibits highly irregular, three-dimensional patterns. This behavior arises due to instabilities in the fluid's velocity profile, and amplifies as the flow velocity increases. Minor disturbances, known as turbulent...
819
01:22Eulerian and Lagrangian Flow Descriptions
2.1K
Fluid flow analysis is critical in many scientific and engineering disciplines, and two principal approaches are used to describe this flow: the Eulerian and Lagrangian methods. These methods offer different perspectives on monitoring and analyzing the motion of fluids, each with distinct advantages depending on the scenario.
The Eulerian method focuses on fixed points in space where fluid properties, such as velocity, pressure, and temperature, are observed as the fluid moves between these...
The Eulerian method focuses on fixed points in space where fluid properties, such as velocity, pressure, and temperature, are observed as the fluid moves between these...
2.1K
01:07Laminar and Turbulent Flow
11.3K
Fluid dynamics is the study of fluids in motion. Velocity vectors are often used to illustrate fluid motion in applications like meteorology. For example, wind—the fluid motion of air in the atmosphere—can be represented by vectors indicating the speed and direction of the wind at any given point on a map. Another method for representing fluid motion is a streamline. A streamline represents the path of a small volume of fluid as it flows. When the flow pattern changes with time, the...
11.3K
01:24Rapidly Varying Flow
575
Rapidly varying flow (RVF) in open channels is characterized by abrupt changes in flow depth over a short distance, with the rate of depth change relative to distance often approaching unity. These flows are inherently complex due to their transient and multi-dimensional nature, making exact analysis difficult. However, approximate solutions using simplified models provide valuable insights into their behavior.Key Features of Rapidly Varying FlowRVF is commonly observed in scenarios involving...
575