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Flow Visualization
Flow visualization or flow visualisation in fluid dynamics is used to make the 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 (air, water, etc.) are transparent, 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 simulating flow processes (e.g. the distribution of air-conditioned air in a new car), purely computational methods have been developed. Methods of visualization In experimental fluid dynamics, flows are visualized by three methods: * Surface flow visualization: This reveals the flow streamlines in the limit as a solid surface is approached. Colored oil applied to the surface of a wind tunnel model provides one example (the oil responds to the surface shear stress and forms a patt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cessna 182 Model-wingtip-vortex
Cessna () is an American brand of general aviation aircraft owned by Textron Aviation since 2014, headquartered in Wichita, Kansas. Originally, it was a brand of the Cessna Aircraft Company, an American general aviation aircraft manufacturing corporation also headquartered in Wichita. The company produced small, Reciprocating engine, piston-powered aircraft, as well as business jets. For much of the mid-to-late 20th century, Cessna was one of the highest-volume and most diverse producers of general aviation aircraft in the world. It was founded in 1927 by Clyde Cessna and Victor Roos and was purchased by General Dynamics in 1985, then by Textron in 1992. In March 2014, when Textron purchased the Beechcraft and Hawker Aircraft corporations, Cessna ceased operations as a subsidiary company, and joined the others as one of the three distinct brands produced by Textron Aviation. Throughout its history, and especially in the years following World War II, Cessna became best known fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Schlieren Photography
Schlieren photography is a process for photographing fluid flow. Invented by the Germans, German physicist August Toepler in 1864 to study supersonic motion, it is widely used in aeronautical engineering to photograph the airflow, flow of air around objects. The process works by imaging the deflections of light rays that are Refraction, refracted by a moving fluid, allowing normally unobservable changes in a fluid's refractive index to be seen. Because changes to flow rate directly affect the refractive index of a fluid, one can therefore photograph a fluid's flow rate (as well as other changes to density, temperature, and pressure) by viewing changes to its refractive index. Using the schlieren photography process, other unobservable fluid changes can also be seen, such as convection currents, and the standing waves used in acoustic levitation. Classical optical system The classical implementation of an optical schlieren system uses light from a single collimated source shin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Skin Friction Lines
In scientific visualization skin friction lines are used to visualize flows on 3D-surfaces. They are obtained by calculating the streamlines of a derived vector field on the surface, the wall shear stress. Skin friction Skin friction drag or viscous drag is a type of aerodynamic or hydrodynamic drag, which is resistant force exerted on an object moving in a fluid. Skin friction drag is caused by the viscosity of fluids and is developed from laminar drag to turb ... arises from the friction of the fluid against the "skin" of the object that is moving through it and forms a vector at each point on the surface. A skin friction line is a curve on the surface tangent to skin friction vectors. A limit streamline is a streamline where the distance normal to the surface tends to zero. Limit streamlines and skin friction lines coincide. The lines can be visualized by placing a viscous film on the surface. The skin friction lines may exhibit a number of different types of singularities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Scientific Visualization
Scientific visualization ( also spelled scientific visualisation) is an interdisciplinary branch of science concerned with the visualization of scientific phenomena. Michael Friendly (2008)"Milestones in the history of thematic cartography, statistical graphics, and data visualization" It is also considered a subset of computer graphics, a branch of computer science. The purpose of scientific visualization is to graphically illustrate scientific data to enable scientists to understand, illustrate, and glean insight from their data. Research into how people read and misread various types of visualizations is helping to determine what types and features of visualizations are most understandable and effective in conveying information. History One of the earliest examples of three-dimensional scientific visualisation was Maxwell's thermodynamic surface, sculpted in clay in 1874 by James Clerk Maxwell. This prefigured modern scientific visualization techniques that use computer gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Rheoscopic Fluid
In fluid mechanics (specifically rheology), rheoscopic fluids are fluids whose internal currents are visible as it flows. Such fluids are effective in visualizing dynamic currents, such as convection and laminar flow. They are microscopic crystalline platelets such as mica, metallic flakes, or fish scales in suspension in a fluid such as water or glycol stearate. When the fluid is put in motion, the suspended particles orient themselves with the local fluid shear. With appropriate illumination, the particle-filled fluid will reflect differing intensities of light. A Kalliroscope is an art device/technique based on rheoscopic fluids (using crystalline guanine as the indicator particleshttps://pubs.aip.org/aip/pof/article/30/8/087103/938850/Rheoscopic-fluids-in-a-post-Kalliroscope-world) invented by artist Paul Matisse. See also * Reynolds number In fluid dynamics, the Reynolds number () is a dimensionless quantity that helps predict fluid flow patterns in different situ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Lagrangian–Eulerian Advection
In scientific visualization, Lagrangian–Eulerian advection is a technique mainly used for the visualization of unsteady flows. The computer graphics generated by the technique can help scientists visualize changes in velocity fields. This technique uses a hybrid Lagrangian and Eulerian specification of the flow field. It is a special case of a line integral convolution. The method consists of using nearest-neighbour interpolation followed by an error correction mechanism. The Lagrangian specification is used during the integration to update the particle positions. The property of interest is advected in the Eulerian frame of reference. It was originally designed by Bruno Jobard and others for steady flows but was extended to unsteady flows. The main idea is to create a white noise texture of the desired resolution, which is used as a base, on top of which the vector field can be applied. That means for every particle looking backward in the vector field to find out the new va ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Image-based Flow Visualization
In scientific visualization, image-based flow visualization (or visualisation) is a computer modelling technique developed by Jarke van Wijk to visualize two dimensional flows of liquids such as water and air, like the wind movement of a tornado. Compared with integration techniques it has the advantage of producing a whole image at every step, as the technique relies upon graphical computing methods for frame-by-frame capture of the model of advective transport of a decaying dye. It is a method from the texture advection family. Principle The core idea is to create a noise texture on a regular grid and then bend this grid according to the flow (the vector field). The bent grid is then sampled at the original grid locations. Thus, the output is a version of the noise, that is displaced according to the flow. The advantage of this approach is that it can be accelerated on modern graphics hardware, thus allowing for real-time Real-time, realtime, or real time may refer to: Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Elementary Flow
In the larger context of the Navier-Stokes equations (and especially in the context of potential theory), elementary flows are basic flows that can be combined, using various techniques, to construct more complex flows. In this article the term "flow" is used interchangeably with the term "solution" due to historical reasons. The techniques involved to create more complex solutions can be for example by superposition, by techniques such as topology or considering them as local solutions on a certain neighborhood, subdomain or boundary layer and to be patched together. Elementary flows can be considered the basic building blocks (fundamental solutions, local solutions and solitons) of the different types of equations derived from the Navier-Stokes equations. Some of the flows reflect specific constraints such as incompressible or irrotational flows, or both, as in the case of potential flow, and some of the flows may be limited to the case of two dimensions. Due to the relationsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Computational Fluid Dynamics
Computational fluid dynamics (CFD) is a branch of fluid mechanics that uses numerical analysis and data structures to analyze and solve problems that involve fluid dynamics, fluid flows. Computers are used to perform the calculations required to simulate the free-stream flow of the fluid, and the interaction of the fluid (liquids and gases) with surfaces defined by Boundary value problem#Boundary value conditions, boundary conditions. With high-speed supercomputers, better solutions can be achieved, and are often required to solve the largest and most complex problems. Ongoing research yields software that improves the accuracy and speed of complex simulation scenarios such as transonic or turbulence, turbulent flows. Initial validation of such software is typically performed using experimental apparatus such as wind tunnels. In addition, previously performed Closed-form solution, analytical or Empirical research, empirical analysis of a particular problem can be used for compa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Texture Advection
In scientific visualization, texture advection is a family of methods to densely visualize vector fields or flows (like the wind movement of a tornado). Scientists can use the created images and animations to better understand these flows and reason about them. In comparison to techniques that visualise streamlines, streaklines, or timelines, methods of this family don't need any seed points and can produce a whole image at every step. The methods have in common that they bend a whole image (or texture) according to the flow to create a new image that is warped by the flow. If that is done in small enough time steps and often enough, the images can be combined to create an animation visualising the flow. Methods * Image-based flow visualization * Lagrangian–Eulerian advection * Line integral convolution In scientific visualization, line integral convolution (LIC) is a method to visualize a vector field (such as fluid motion) at high spatial resolutions. The LIC technique ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Streamlines, Streaklines, And Pathlines
Streamlines, streaklines and pathlines are field lines in a fluid flow. They differ only when the flow changes with time, that is, when the flow is not steady flow, steady. Considering a velocity vector field in three-dimensional space in the framework of continuum mechanics: * Streamlines are a family of curves whose tangent vectors constitute the velocity vector field of the flow. These show the direction in which a massless fluid element will travel at any point in time. * Streaklines are the Locus (mathematics), loci of points of all the fluid particles that have passed continuously through a particular spatial point in the past. Dye steadily injected into the fluid at a fixed point (as in dye tracing) extends along a streakline. * Pathlines are the trajectory, trajectories that individual fluid particles follow. These can be thought of as "recording" the path of a fluid element in the flow over a certain period. The direction the path takes will be determined by the stre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Scientific Visualization
Scientific visualization ( also spelled scientific visualisation) is an interdisciplinary branch of science concerned with the visualization of scientific phenomena. Michael Friendly (2008)"Milestones in the history of thematic cartography, statistical graphics, and data visualization" It is also considered a subset of computer graphics, a branch of computer science. The purpose of scientific visualization is to graphically illustrate scientific data to enable scientists to understand, illustrate, and glean insight from their data. Research into how people read and misread various types of visualizations is helping to determine what types and features of visualizations are most understandable and effective in conveying information. History One of the earliest examples of three-dimensional scientific visualisation was Maxwell's thermodynamic surface, sculpted in clay in 1874 by James Clerk Maxwell. This prefigured modern scientific visualization techniques that use computer gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |