To study laminar and turbulent flows, researchers use different tools and methods. Each tool is important because it helps us understand how fluids move in different situations.

1. Experimental Methods:

• Wind Tunnels:
  Wind tunnels are used to see how air flows. They create a controlled space to observe flow patterns. This helps scientists learn about boundary layers (where flow changes) and where the flow separates from surfaces.

• Water Channels:
  These are like wind tunnels but for water. They let scientists look closely at laminar flow, which is smooth, over surfaces.

2. Computational Fluid Dynamics (CFD):

• CFD uses computers to simulate fluid movement. It helps solve the Navier-Stokes equations, which explain how fluids behave.

• Programs like ANSYS Fluent and OpenFOAM help scientists understand both laminar and turbulent flows through simulations.

• Special turbulence models (like RANS, LES, and DNS) help analyze how complex flows interact with each other.

3. Flow Visualization Techniques:

• Particle Image Velocimetry (PIV):
  This method measures how fast the fluid is moving at different points. It shows the flow fields clearly, helping to tell the difference between laminar and turbulent flows.

• Smoke or Dye Injection:
  This simple method helps visualize flow patterns. It shows how laminar flow stays smooth, while turbulent flow mixes rapidly.

4. Dimensional Analysis:

• Researchers use non-dimensional numbers, like the Reynolds number ($Re$), to describe flow types. A low $Re$ number means the flow is laminar, while a high $Re$ number indicates turbulence.

5. Theoretical Approaches:

• The Alfred equation gives insights into when laminar flow changes to turbulent flow. The critical Reynolds number for this change can be written as:
  $Re_{crit} = \frac{\rho v L}{\mu}.$

By using these tools and methods together, scientists can gain a deep understanding of how fluids behave. This knowledge helps improve engineering projects and studies of natural events in fluid mechanics.