User talk:Cccefalon/Archives/ - Wikimedia Commons
Ich kann gut ohne QIC leben. Mehr gibt es dazu meiner Meinung nach auf meiner Talkpage nicht zu sagen; wenn es unbedingt sein muss, dann bitte ich darum, auf dem QIC talk weiter zu diskutieren. This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. Mauritius Seven-Coloured-Earths We also invite you to take part in the categorization of recently promoted quality images.
Namespaces User page Discussion. This applies for the velocity acting on the pappus at an average wall-normal distance of 7mm apart from the wall. At flow speeds above 1. Beyond that, the plot shows a 20dB roll-off which is typical for an overdamped mechanical system [ 8 ].
The damping results mostly from the high aerodynamic resistance of the pappus in the relaxing motion. It is only marginally influenced by the internal damping of the membrane. This is illustrated by comparing the difference in step response behavior for the stalk with complete pappus and for solely the stalk after cutting-off all hairs, see also S1 Appendix. The reference flow situation with the wall-jet generated in the isothermal chamber is used as an in-situ calibration to qualify the sensor for the intended studies of turbulent convection flows close to the walls of the large convection cell.
Wall-bounded flows form a velocity profile along the wall-normal direction as observed in natural convection flow in the barrel near the walls, too. The wall-jet device is designed to generate a two-dimensional boundary layer flow directed towards the sensor with a similar velocity and scale at the location of the sensor as measured in earlier studies of convection flows in the barrel [ 20 ]. Focus of the tests of the sensor is the response against a quasi-steady flow situation at different flow direction towards the sensor.
Such a quasi-steady flow at the sensor-location is achieved only for slot exit velocities between 0. The lower bound is given by the fact that a certain limit of fan speed was required to generate a constant flow rate at the slot exit. On the other hand, above a slot exit velocity of 0. The measured turbulence level of the outlet flow was less than 0.
These measurements showed also that after the start of the fan it takes about 6 seconds until the flow at the exit gets quasi-steady. The latency is due to the run-up of the fan and built-up of pressure in the wall-jet facility. As the flow Reynolds-number in our experiments is lower, the distance required to approach this solution also decreases [ 17 ]. The measured velocity profile is in good agreement with a fit with the self-similar Blasius jet solution [ 13 ] as shown in Fig 5.
The effect of wall inclination on the mean flow in a two-dimensional wall jet has been studied by Lai and Lu [ 18 ]. A typical record of the tip motion in streamwise direction as recorded with the camera from top is shown in Fig 6. The rms value of the tip motion after the initial transient is about 10micron which is 1.
The result is given in Fig 7. Power spectrum of the tip motion signal after start of the jet-flow in the quasi-steady state shown in Fig 6. The dominant peak is at a frequency of 0. The peak corresponds to the fundamental frequency of the primary instability of the jet as discussed below. The procedure was repeated for different exit velocities of the wall-jet in the range between 0.
The resulting relation has an rms error of 0. Based on the theoretically linear relation between drag and velocity for the low Reynolds-number flow around the tiny hairs it is assumed that this regression holds also for lower velocities which we however could not generate with the facility as a steady flow situation. The tests of the sensor at different flow directions of the wall-jet in north, east, south and west showed that the tip bending can vary sometimes up to 10micron at 0.
This inequality is caused by a non-perfect bonding of the stem to the membrane which should ideally be such that the stem is exact perpendicular to the wall. Although maximum care was taken in this bonding process using the help of a three-axes micrometer traverse the result was not always perfect. Therefore the directional flow tests were used to select only those sensors for further measurements which show less than 4micron of tip bending difference, see Fig 8.
This is equivalent to a velocity fluctuation of 0. Directional response of the sensors for four different wind-directions generated with the wall-jet facility north N, east E, south S, west W.
The plot shows at the cross-symbols the mean response of the qualified sensor and the diameter of the small circles indicate the variation of all others being tested, partly failing to comply with our quality criterion. The larger dashed circles indicate the tested velocity of the jet flow. Note, that the tip displacement coordinates of Q are related to the x-y plane of the camera sensor parallel to the bottom wall.
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The coordinate system of the camera was rotated such that the direction to North is parallel to the positive y-direction in the plot. The observed increase of the variation with increase of jet velocity, especially beyond 0. This is because we are recoding in the calibrations with a frequency of 10Hz and the growing fluctuations in the jet flow at continuous illumination blur the image which deteriorate the peak detection algorithm.
This can be circumvented with a high-intensity pulsed light source, which is now in use for the future measurements. The calibration with the wall-jet flow is reproducible and tests with varying jet flow directions in the horizontal plane from north, east, south and west showed for the selected sensor structure only marginal differences of less than 4micron in tip bending for the different flow directions at maximum flow speeds of 0.
As the hairs of the pappus are directed radially outwards and their tips form the segment of a sphere, the drag onto the pappus is assumed to be indifferent to the angular direction of the flow in the horizontal plane. The nonetheless observed deviation is attributed to the bonding of the stem to the membrane which should ideally be the stem axis perpendicular to the wall. Only those sensors were finally used which passed the directional tests with sufficient small angular deviations.
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The force on the pappus represents an average of the wind-induced drag along the individual hairs which see different speed and orientation against the local flow vector. Our measurements of the wall-jet flow therefore represent an average drag induced by the local velocity profile near the wall in a height of about 7mm at the tip the pappus. This integration effect limits the spatial resolution of the sensor in its current configuration with the Dandelion pappus, however the sensor size is still appropriate for the intended research of large-scale convection flows such as those in the Ilmenau barrel, where the smallest scales of fluctuations in studies at high Rayleigh-numbers up to 10 12 were in the centimeter-scale, too [ 20 ].
We designed the wall-jet facility accordingly to generate a velocity and thickness of the boundary layer flow similar as observed in the barrel. Note that also much smaller pappus structures can be found in nature and can be used for our sensors, which however was not necessary for the purpose of the study.
The large number of small hairs of the pappus contributing to the total drag at the tip of the stem is the key to achieve the high sensitivity to minute air motions. Closer to the wall the velocity tends to decrease to zero which makes it increasingly difficult to sense the flow with smaller sensors. The detection threshold is given by the optical resolution of the imaging system which needs to resolve smallest differences in tip motion between wind-on and wind-off situation at a distance of 2m away from the sensory structure outside the barrel.
Currently, this resolution is a tip-displacement of 0. This is equivalent to the biological threshold reported in [ 1 , 2 ]. A combination of both, increased magnification and pixel format would even allow to measure with the sensor below the biological threshold. Further response tests were done with the pappus sensor before and after cutting-off all hairs from the stem.
This comparison demonstrates that the viscoelastic relaxation in the membrane is not affecting the sensor response time for time-scales larger than the response time. With the sensor response time and detection threshold one can determine the Figure of Merit FOM as the inverse of the product of both.
As the dynamic sensor response is approximately constant up to frequencies of about Hz, it is qualified for investigations of turbulent flows containing coherent motions that vary in times-scales of 10ms and larger. Note, that the use of such pappus-type sensors for other applications and higher frequencies is possible, which requires the adaptation of the size and mechanical properties of the pappus and the membrane in a joint optimization process. This frequency agrees with the most amplified frequency of the Blasius shear layer predicted from theory.
It is clear that under natural conditions, the wall jet operates in unforced mode and a broad band of frequencies it amplified. This demonstrates that the pappus sensor is able to detect the weak disturbances of wave-type instabilities present in the quasi-steady wall-jet flow. Nature is used herein to build a pappus-type flow sensor which is applied to measure from remote distances optically minute air-flow motions near walls.
The sensing principle is based on the measurement of transversal displacement of the tip of the pappus due to the drag force, which the air flow is inducing on it. Thanks for all your work with this excelent psx plugins.
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Note: I'm not a English-speaker, forgive me my cheap ortografic. By all means keep doing what you do so well, and just know you are very appreciated around here! Thank you in advance pete. Your plugins are awesome! Your plugins are freakin awesome. Can you also make a plugin for Glide 3. I have the game Final Fantasy 7, and everything is good in your plugin when i play, everything, even speed is fine It gives me an error like this : P.
S : it's never the same error, but it's this one mostly: Sorry, my computer is in french, but ill try to translate it DLL at ccd. I don't know what to do lol I'm not a proffessionnal in computers, but i still know some basics When i put Pete OpenGl things on, it works, but the fps speed is like 35, And I can't see what they say in game, nothing appears in the chat boxes Help me please lol I would really appreciate Yoce I tried to send this message to BlackDove addcom.
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Congratulations dude, you rule!!!! Thank you very much. Glad to see some update or improvement from you. Thanks for continuing your great PSX plugin development. The runs vry good until i try to use some magic. Think WHO will do plugins if not you :D!
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And every day I'm getting more and more sure that it was a good choice. Thanks for all that hardwork. Thanks for you fabulous work especially for the linux ports!!! After so long what a disappointment. I just want to say that you are doing a great job!
Thank you! Go on like this! I own a playstation that doesnt work and i hate lugging around my playstation2. So I put a playstation emulator on my laptop using Pete's Plugins and could not be happy. Pete, you should start making something in the way for Playstation 2. Thanks to Pete's.