Here are some pictures related to fluid sciences. A paragraph of explanation and background is given for each picture, suitable for general reading. I might elaborate later on some of them as separate notes with more technical details.
CFD stands for Computational Fluid Dynamics. It is one of the branches of fluid mechanics that uses numerical methods to algebraize partial and ordinary differential equations (that represent fluid flow) and use algorithms to perform iterative operations seeking solutions to those algebraic equations. In general, it is a way to solve equations that describe fluid flow through iterative schemes that are amenable to be programmed and solved using computers. At times, CFD can be a cheap substitute for expensive experiments. On occasions, it is the only way to understand fluid flow. Like this example of computationally simulated fluid flow around a Protoceratops
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Categories: Fluid Sciences · Physics · Science
Tagged: cfd, fluid mechanics, bladeless fan, cerebral fluid, protoceratopus, rayleigh taylor instability
Irreversibility in thermodynamics is usually explained with a movie example. A movie strip when rewound, wounds back in time, the events it evolved forward in time. Events in life do not usually reverse completely – unless, reality is what is depicted as in The Matrix. Movies are completely reversible. But reality is not so.
But here is a simple and elegant real-life fluid mechanics experiment that is reversible. Take two concentric cylindrical containers made of transparent glass or perspex. The cylinders are of different diameters and placed one inside the other. The inner cylinder is fixed to a motor from the top and it can be made to rotate at fixed speeds. A small gap separates the bottom surface of the inner cylinder from that of the outer cylinder. The annular space is filled with a highly viscous fluid. Say honey or Golden Syrup. Put a blob of ink or colouring agent using an ink filler somewhere inside the fluid, away from all of the cylinder walls. This configuration is shown as the first diagram in the accompanying schematic.
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Categories: Fluid Sciences · Physics · Science
Tagged: fluid mechanics, reynolds number, laminar flow, reversibility, experiment, low reynolds number, viscous flows
