Turbulence Model Selection for Low Reynolds Number Flows

Area of Science:

• Fluid dynamics
• Aerodynamics
• Computational fluid dynamics

Background:

• Low Reynolds number flow often features laminar separation bubbles on airfoils.
• NACA4415 airfoils are prevalent in wind turbines and UAVs, exhibiting gradual stall characteristics.
• Accurate simulation of laminar separation bubbles is crucial for predicting airfoil performance.

Purpose of the Study:

• To evaluate the performance of different turbulence models in capturing laminar separation bubbles on a NACA4415 airfoil.
• To analyze the advantages and disadvantages of various turbulence models for low Reynolds number flow.
• To establish a validated simulation procedure by comparing with experimental results.

Main Methods:

• Numerical simulation of flow around a NACA4415 airfoil at a Reynolds number of 120,000.
• Implementation and comparison of multiple turbulence models: Spallart-Allmaras (S-A), SST K-ω, Intermittency (γ) SST, k-kl-ω, and transition γ-Reθ SST.
• Validation of simulation accuracy against established experimental data.

Main Results:

• Different turbulence models exhibit variations in capturing the flow physics, particularly the laminar separation bubble.
• The study details the specific advantages and disadvantages of each tested turbulence model.
• A methodology for ensuring simulation accuracy aligned with experimental findings is presented.

Conclusions:

• The choice of turbulence model significantly impacts the prediction of laminar separation bubbles in low Reynolds number flows.
• Accurate simulation requires careful selection and validation of turbulence models against experimental data.
• Understanding these models is key for optimizing airfoil design in wind turbine and UAV applications.