As an alternative to fluid simulations requiring high computational power, rheoscopic fluids can be used for practical purposes when considering the Reynolds number or for qualitative flow observations. [Visual Thinker] prepared this fluid by adding mica flakes to water and, when necessary, a drop of soap to prevent clumping. The reflective mica flakes, which align with the shear of the flow, make its movements visible. The method was first tested in a setup showing the flow around a Benchy body moved by magnets, and then in a wind tunnel made of laser-cut acrylic and printed parts.
Why it matters
This approach shows that simulations based on high computational power may not always be necessary for those who want to study fluid behavior. The alignment of the mica flakes with the shear makes movements that are difficult to detect directly visible, facilitating qualitative observations in particular. The fact that it can be prepared with water, mica and a small amount of soap also makes the method suitable for do-it-yourself applications outside the laboratory. Testing it in setups with a magnetically moved body and a wind tunnel demonstrates that the same principle can be used to examine different flow conditions. However, as also stated in the text, this method is intended not so much to produce all the results of computational simulation as to enable practical observation and make the general behavior of the flow visible.