Lagrangian Approach for Turbulent Flow Analysis and Particle Tracking in a Channel

One of the established and modern approaches for analyzing turbulent flows is particle tracking and analyzing their behavior. A combination of a high-order numerical integration method and a high-order interpolation technique is required to track particles. In the present study, the DNS data is first visualized using the Q-criterion. After visualizing the structures, specific ones are selected for tracking. For simplicity, a point is selected as a representative of the structure, which is treated as a 'particle' in the subsequent analysis. Here, the term 'large particle' refers to a large structure, while 'small particle' refers to a small structure. The particles are then tracked using the fourth-order Runge-Kutta method and fifth-order Lagrange interpolation. The findings revealed that larger particles tend to follow more direct paths with fewer fluctuations compared to smaller particles. Additionally, particles in high-velocity regions of the channel travel longer distances and exhibit fewer oscillations along their trajectories compared to those in low-velocity regions. These velocity differences cause structures formed perpendicular to the flow to stretch along the flow direction. This study highlights the importance of particle tracking in understanding turbulent flows and provides insights into the influence of particle size and velocity regions on flow behavior. The methodology can be further extended to more complex geometries and flow conditions in future research.

کلیدواژه ها:

Coherent structure ، Turbulent channel flow ، Tracking ، Visualization