https://album-of-cfm.com/ Recent content on An album of computational fluid motion Hugo -- gohugo.io en Wed, 01 May 2024 00:00:00 +0000 https://album-of-cfm.com/chapters/01-creeping/fig1/ Sat, 08 Apr 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/01-creeping/fig1/ ExperimentSimulation “Dye shows the streamlines in water flowing at 1 mm per second between glass plates spaced 1 mm apart. It is at first sight paradoxical that the best way of producing the unseparated pattern of plane potential flow past a bluff object, which would be spoiled by separation in a real fluid of even the slightest viscosity, is to go to the oposite of extreme of creeping flow in a narrow gap, which is dominated by viscous forces. https://album-of-cfm.com/chapters/02-laminar/fig24/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/02-laminar/fig24/ ExperimentSimulation “At this Reynolds number the streamline pattern has clearly lost the fore-and-aft symmetry of figure 6. However, the flow has not yet separated at the rear. That begins at about R=5, though the value is not known accurately. https://album-of-cfm.com/chapters/03-separation/fig35/ Wed, 14 Jun 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig35/ ExperimentSimulation Air bubbles in water show the turbulent flow field and laminar reattachment on an inclined plate at Reynolds number \(Re = 10000\). At \(2.5^{\circ}\) inclination relative to the oncoming flow, the flow briefly separates from the upper surface at the leading edge before it reattaches to the inclined plate. https://album-of-cfm.com/chapters/03-separation/fig36/ Sun, 18 Jun 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig36/ ExperimentSimulation Air bubbles in water show the turbulent flow field and turbulent reattachment on an inclined plate at Reynolds number \(Re = 50000\). At 2.5\(^{\circ}\) inclination relative to the oncoming flow, the flow separates from the upper surface, creating a turbulent boundary layer at the leading edge before reattaching to the inclined plate. https://album-of-cfm.com/chapters/03-separation/fig37/ Fri, 30 Jun 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig37/ ExperimentSimulation Air bubbles in water show the turbulent flow field around an inclined plate at Reynolds number \(Re = 10000\). At 20\(^{\circ}\) inclination relative to the oncoming flow, the flow fully separates from the entire upper surface of the plate and creates a turbulent wake. https://album-of-cfm.com/chapters/03-separation/fig40/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig40/ ExperimentSimulation “Here, in contrast to figure 24, the flow has clearly separated to form a pair of recirculating eddies. The cylinder is moving through a tank of water containing aluminum powder, and is illuminated by a sheet of light below the tree surface. https://album-of-cfm.com/chapters/03-separation/fig41/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig41/ ExperimentSimulation “The standing eddies become elongated in the flow direction as the speed increases. Their length is found to increase linearly with Reynolds number until the flow becomes unstable above R=40. https://album-of-cfm.com/chapters/03-separation/fig42/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig42/ ExperimentSimulation “The downstream distance to the cores of the eddies also increases linearly with Reynolds number. However, the lateral distance between the cores appears to grow more nearly as the square root. https://album-of-cfm.com/chapters/03-separation/fig45/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig45/ ExperimentSimulation “Here just the boundary of the recirculating region has been made visible by coating the cylinder with condensed milk and setting it in motion through water.” Photograph by Sadathoshi Taneda https://album-of-cfm.com/chapters/03-separation/fig46/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig46/ ExperimentSimulation “This is the approximate upper limit for steady flow. Far downstream the wake has already begun to oscillate sinusoidally. Tiny irregular gathers are appearing on the boundary of the recirculating region, but dying out as they reach its downstream end. https://album-of-cfm.com/chapters/03-separation/fig47/ Thu, 11 May 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/03-separation/fig47/ ExperimentSimulation “Air bubbles in water show the velocity field of a flow around a circular cylinder at Reynolds number \(Re = 2000\). At this Reynolds number, there is a clear boundary layer separation followed by an oscillating turbulent wake. https://album-of-cfm.com/chapters/04-vortices/fig94/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/04-vortices/fig94/ ExperimentSimulation “Water is flowing at 1.4 cm/s past a cylinder of diameter 1cm. Integrated streamlines are shown by electrolytic precipitation of white colloidal smoke, illuminated by a sheet of light. https://album-of-cfm.com/chapters/04-vortices/fig96/ Fri, 18 Aug 2023 00:00:00 +0000 https://album-of-cfm.com/chapters/04-vortices/fig96/ ExperimentSimulation “The initially spreading wake shown opposite develops into the two parallel rows of staggered vortices that von Kármàn’s inviscid theory shows to be stable when the ratio of width to streamwise spacing is 0. https://album-of-cfm.com/chapters/05-instability/fig103/ Sun, 04 Feb 2024 00:00:00 +0000 https://album-of-cfm.com/chapters/05-instability/fig103/ ExperimentSimulation “Osborne Reynolds’ celebrated 1883 investigation of stability of flow in a tube was documented by sketches rather than photography. However the original apparatus has survived at the University of Manchester. https://album-of-cfm.com/chapters/08-convection/fig204/ Wed, 10 Apr 2024 00:00:00 +0000 https://album-of-cfm.com/chapters/08-convection/fig204/ ExperimentSimulation “The plate is uniformly heated in air, producing a steady laminar flow. An interferogram shows lines of constant density which, at nearly constant pressure, are also isotherms. The Grashof number is approximately five million at a distance of 0. https://album-of-cfm.com/chapters/09-subsonic/fig223/ Wed, 01 May 2024 00:00:00 +0000 https://album-of-cfm.com/chapters/09-subsonic/fig223/ ExperimentSimulation $$ \vcenter{M = 0.840} $$ ExperimentSimulation $$ \vcenter{M = 0.885} $$ ExperimentSimulation $$ \vcenter{M = 0.900} $$ ExperimentSimulation $$ \vcenter{M = 0.946} $$ ExperimentSimulation $$ \vcenter{M = 0.971} $$ “The spark shadowgraphs on these two pages have been arranged to show the shock-wave pattern growing into the subsonic field around a model of an artillery shell as its Mach number is increased. https://album-of-cfm.com/chapters/09-subsonic/fig224/ Wed, 01 May 2024 00:00:00 +0000 https://album-of-cfm.com/chapters/09-subsonic/fig224/ ExperimentSimulation $$ \vcenter{M = 0.978} $$ ExperimentSimulation $$ \vcenter{M = 0.990} $$ “Still closer to the speed of sound, the shock-wave pattern of the preceding pages had spread laterally to great distances. https://album-of-cfm.com/chapters/11-supersonic/fig253/ Wed, 01 May 2024 00:00:00 +0000 https://album-of-cfm.com/chapters/11-supersonic/fig253/ ExperimentSimulation “The model artillery shell of figures 223 and 224 is shown here still earlier in its trajectory, when it is flying at a slightly supersonic speed. A detached bow wave precedes it, and the distant field is quite different, but the pattern near the body is almost identical to that shown in figure 224 for a slightly subsonic speed.