👉 A boundary fluid, also known as a boundary layer fluid or shear fluid, is a fluid that exists at the interface between two media with different properties, typically at high velocity gradients or near solid surfaces. This fluid plays a crucial role in the transfer of momentum and heat between these media, significantly influencing the behavior of fluid flow. In practical terms, boundary fluids are often found in situations like airflow over an airplane wing or blood flow near a heart valve, where the interaction between the fluid and the solid surface is critical for understanding and predicting flow dynamics, heat transfer, and overall system performance.
