# Flow visualization > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Flow_visualization > Markdown URL: https://mediated.wiki/source/Flow_visualization.md > Source: https://en.wikipedia.org/wiki/Flow_visualization > Source revision: 1318259056 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Visualization technique in fluid dynamics}} {{More footnotes|date=April 2009}} [[File:Cessna 182 model-wingtip-vortex.jpg|thumb|320px|A model [Cessna](/source/Cessna) with helium-filled bubbles showing [pathlines](/source/Streamlines%2C_streaklines_and_pathlines) of the [wingtip vortices](/source/wingtip_vortices).]] '''Flow visualization''' or '''flow visualisation''' in [fluid dynamics](/source/fluid_dynamics) is used to make the [flow](/source/fluid_flow) patterns visible, in order to get qualitative or quantitative information on them. == Overview == Flow visualization is the art of making flow patterns visible. Most [fluids](/source/fluids) (air, water, etc.) are [transparent](/source/Transparency_(optics)), thus their flow patterns are invisible to the naked eye without methods to make them this visible. Historically, such methods included experimental methods. With the development of computer models and [CFD](/source/Computational_fluid_dynamics) simulating flow processes (e.g. the distribution of air-conditioned air in a new car), purely computational methods have been developed. == Methods of visualization == [[File:shadowgram-gas-grill.jpg|thumb|[Shadowgraph](/source/Shadowgraph) of the turbulent [plume](/source/Plume_(fluid_dynamics)) of hot air rising from a home-barbecue gas grill. Photograph by Gary S. Settles, Floviz Inc.]] In [experimental fluid dynamics](/source/experimental_fluid_dynamics), flows are visualized by three methods: * Surface flow visualization: This reveals the flow [streamlines](/source/Streamlines%2C_streaklines_and_pathlines) in the limit as a solid surface is approached. Colored oil applied to the surface of a [wind tunnel](/source/wind_tunnel) model provides one example (the oil responds to the surface [shear stress](/source/shear_stress) and forms a pattern). * Particle tracer methods: Particles, such as smoke or [microspheres](/source/microspheres), can be added to a flow to trace the fluid motion. We can illuminate the particles with a sheet of [laser](/source/laser) light in order to visualize a slice of a complicated fluid flow pattern. Assuming that the particles faithfully follow the streamlines of the flow, we can not only visualize the flow but also measure its velocity using the [particle image velocimetry](/source/particle_image_velocimetry) or [particle tracking velocimetry](/source/particle_tracking_velocimetry) methods. Particles with densities that match that of the fluid flow will exhibit the most accurate visualization.http://microspheres.us/fluorescent-microspheres/piv-seeding-microparticle-flow-visualization/599.html PIV seeding particle recommendations * Optical methods: Some flows reveal their patterns by way of changes in their optical [refractive index](/source/refractive_index). These are visualized by optical methods known as the [shadowgraph](/source/shadowgraph), [schlieren photography](/source/schlieren_photography), and [interferometry](/source/interferometry). More directly, dyes can be added to (usually liquid) flows to measure concentrations; typically employing the [light attenuation](/source/light_attenuation) or [laser-induced fluorescence](/source/laser-induced_fluorescence) techniques. In [scientific visualization](/source/scientific_visualization) flows are visualized with two main methods: * Analytical methods that analyse a given flow and show properties like [streamlines, streaklines, and pathlines](/source/streamlines%2C_streaklines%2C_and_pathlines). The flow can either be given in a finite representation or as a smooth function. * [Texture advection](/source/Texture_advection) methods that "bend" textures (or images) according to the flow. As the image is always finite (the flow through could be given as a smooth function), these methods will visualize approximations of the real flow. == Application == In [computational fluid dynamics](/source/computational_fluid_dynamics) the numerical solution of the governing equations can yield all the fluid properties in space and time. This overwhelming amount of information must be displayed in a meaningful form. Thus flow visualization is equally important in computational as in experimental fluid dynamics. == See also == {{Div col|colwidth=20em}} * [Elementary flow](/source/Elementary_flow) * [Image-based flow visualization](/source/Image-based_flow_visualization) * [Lagrangian–Eulerian advection](/source/Lagrangian%E2%80%93Eulerian_advection) * [Rheoscopic fluid](/source/Rheoscopic_fluid) * [Scientific visualization](/source/Scientific_visualization) * [Skin friction lines](/source/Skin_friction_lines) * [Streamlet (scientific visualization)](/source/Streamlet_(scientific_visualization)) * [Streamlines, streaklines and pathlines](/source/Streamlines%2C_streaklines_and_pathlines) * [Streamsurface](/source/Streamsurface) * [Tensor glyph](/source/Tensor_glyph) * [Texture advection](/source/Texture_advection) * [Vortex core line](/source/Vortex_core_line) {{Div col end}} == References == * {{cite book |last=Merzkirch | first=W. |title=Flow visualization |location=New York | publisher=Academic Press |year=1987 |isbn=0-12-491351-2}} * {{cite book |author-link=Milton Van Dyke |last=Van Dyke | first=M. |title=[An album of fluid motion](/source/An_album_of_fluid_motion) |location= Stanford, CA |publisher=Parabolic Press |year=1982 |isbn=0-915760-03-7}} * {{cite book |last1=Samimy |first1=M. | last2=Breuer |first2=K. S. |last3=Leal |first3=L. G. |last4=Steen |first4=P. H. |title=A gallery of fluid motion |publisher=Cambridge University Press |year=2004 |isbn=0-521-82773-6}} * {{cite book |last=Settles |first=G. S. |title=Schlieren and shadowgraph techniques: Visualizing phenomena in transparent media |location=Berlin |publisher=Springer-Verlag |year=2001 |isbn=3-540-66155-7}} * {{cite book |last1=Smits |first1=A. J. |last2=Lim |first2=T. T. |title=Flow visualization: Techniques and examples |publisher=Imperial College Press |year=2000 |isbn=1-86094-193-1}} {{Reflist}} == External links == {{Commons category|Flow visualization}} *[http://www.cg.tuwien.ac.at/~helwig/diss/node10.htm Flow visualization techniques] {{Webarchive|url=https://web.archive.org/web/20110523100520/http://www.cg.tuwien.ac.at/~helwig/diss/node10.htm |date=2011-05-23 }}. *[https://web.archive.org/web/20070928023426/https://visualization.hpc.mil/wiki/index.php/Visualization_Algorithms Flow visualization algorithms]. *[http://www.flowvis.org Gallery of Flow Visualization Examples.] *[https://web.archive.org/web/20080307024636/http://www.interactiveflows.com/links/ Educational Particle Image Velocimetry (e-PIV) - resources and demonstrations] {{Visualization}} Category:Flow visualization --- Adapted from the Wikipedia article [Flow visualization](https://en.wikipedia.org/wiki/Flow_visualization) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Flow_visualization?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.