Vortism a Basic Art - ploland.deploland.de/Gruku-PDF/Scart-Vortismus.pdf · jets can be free, swirling or wall jets, Recknagel Sprenger (RS) (1999). A use of vortistic iconography

3. Conference on Flow Interaction with Exhibition/ Lectures on Interaction of Science and Art28.2.-3.3. 2000 ETH Zürich

CD/ Scart -Text - 03.09.06 18:06 -1- Plotter/Koppenwallner

Vortism a Basic ArtGeorg Emanuel Koppenwallner und Ludwig Plotter,

D-37085 Göttingen/ GermanyHimmelsstieg 1 / Fax – 0049 551 7989512

Abstract: Basic art is an effort to fill the gap between science and art. Vortism usesvortices as iconographic symbols. These symbols can be combined to create synopticimaginations for painting. They can also explain in a more image-like fashion flowphenomena in bionics or technics. This can be applied to invent new machines andideas. The adaption of vortism in suction devices is presented. The terms frontal-flow,frontal-vortex and Coanda-vortex are introduced. The swimming of fluidic-beingsthunas and sharks is presented in a vortistic manner. The relation between science andart is shown from both sides. A turntable experiment is proposed that is inspired by thebasic art of vortism. This experiment shall use frontal- vortex generators.

Keywords: Vortism, Coanda, Basic Art, Painting, Invention

1.WHY ART - WHY BASIC ART

Out of a technical point of view art is the human ability to create material things. Out ofa more mental angle of view art is the human ability to create imaginations. We shareand cultivate these imaginations until they influence our lives. Human evolution, laterhuman history, human technical and social development shows a lot of these livegoverning cultivations. These are: Thougts, things, rituals, religious believes, socialorders, technical know how, science etc. . But our often narrow minded reception of theworld does not longer fit to our global possibilitiesThe global society works still mainly on the death line [=Todeslinie] Beuys (1976).Technical applications are evolving into mass production, mass consumption causingmass destruction and mass nature changes. Joseph Beuys postulated the idea of a socialplastic [=Soziale Plastik] to de-imaginaze the old system by the aid of all individuals.Everybody is creating the social plastic. That sounds difficult and is difficult. But art isthe tool or more mental the idea to manage this. Basic art shall help to shape this socialplastic.Art is more than creating things and having thougts. Art is also a source of emotion.We can neither understand our world in details nor in totality. But we must act andsurvive in this world. Art is a human way to do this. Art does not create theories thatbecome more and more restricted or even false. Artworks remain as true as the emotionsbehind.We observe today an increasing drift between highly specialized knowledge and morecomplex and universal points of view. This is a big problem.



A basic art shall not be a concurrence to isolated sciences. It shall bridge the regionsexcluded for sciences on the one side and for the multimedial blindness on the otherside.Art is already a method to be applied to the structure of houses, planes, submarines orcars. We may call this work architecture, industrial design, bionics or ingeneering. Apiece of art is always included. All these applied arts must be usefull, practical and ofeconomical, scientific or other practical value. Pure art can be more related to humor,nonsense and other dangers of strict orders and rigid systems. Basic art shall form thefundamentals to more synoptic views of our world. In computional simulations we needdiagnostic fields to create prognostic fields. We need arts to find or invent new imagesthat are forerunners of scientific, technical and political ideas

2. VORTISM A BASIC ART

Vortism uses vortices as iconographic elements. The most common examples are themonopolar vortex (source-sink flow), the bipolar vortex (convection) and the tripolarvortex (a common instability mode of monopolar vortices especially in rotatingsystems). Vortices of varying scales are a common phenomena in flows about a certainReynolds-number. This phenomena of complex vortex interaction is termed turbulence,a 'parametrization' of non-understanding. In technical situations it is often usefull tocontrol or to remove such flows. This is of growing importance in a future of restrictedenergy consumption. But to understand turbulent flows interacting with theirsurrounding is just one feature of ‚hopeless‘ many influences on beings that are living ormachines that are working with or in fluids. Basic art tries to regard all these influences.

2.1 Vortism in suction devices

Human skill creates artificial atmospheres in houses, production halls, ships, planes etc..To remove polluted gas is a daily event also in kitchens. Above the oven is often acooker hood. The common way to increase suction efficiency there is to increase flowrate.

A more sophisticated method is the use of jet flows towards the suction areas. Thesejets can be free, swirling or wall jets, Recknagel Sprenger (RS) (1999). A use ofvortistic iconography shall show the situation in suction devices. A thermal jetascending from a heat source hits a horizontal boundary and spreads as a kind of densitycurrent under this plane. If the flow is more heavy compared to the surrounding we justhave to turn this drawing, Fig. 1 a), b). The plane can contain a suction area and iscomparable to a cooker hood.



Figure 1. Density currents and thermal flows a) ρ < ρ umg , b) ρ > ρ umg

The suction flow velocity u is rapidly decreasing in a distance x form the opening, RS(1999) p. 1643.

u (x) ~ ²

1x

, )0(

)(=xuxu = C *

AxA

+²10

A is the area of an rectangular or circular suction mound. It is C = 1 for a free openingand C = 1,33 for a mound with a flange. One diameter in distance the suction velocity isreduced to about 10%.To control density currents around suction openings at undersides the use of frontalflows increases suction efficiency

Fig. 2. Frontal-vortex generators, a) Coanda-vortex b) Jet-vortex (Strahlwirbel) type

The flow 2 a) is a circular shear flow near a surface. The flow 2 b) is a vortex flow neara surface. Both flows create a dynamical front near the surface. I propose for theseflows the term: Frontal flow.

1 a)

1 b)

Dynamical Front Dynamical Front

Coanda Vortex

Frontal flow Frontal flow

Jet-Vortex



Fig. 2 shows two different types of frontal vortex generators. I also propose the termCoanda-vortex for a vortex without core, Fig. 2 a). So it is possible to say:Frontal-vortices stop and reverse escaping density-flows and thermals near boundaries.These kinds of frontal-vortex generators are applied in cooker hoods and other suctiondevices. Fig. 2 c) shows the principle of a frontal vortex cooker hood. At the left is aschlierenfoto of the frontal region.

Fig. 2 c ) Principle of a frontal vortex cooker hood, left Schlierenfoto of the flow

The coanda effect is named after H. Coanda (1932) who described the jet to wall andjet to jet attachment in a patent .The parameter range is described in terms of a Re-number. Fig. 3 b) shows a typicalexperimental setup. Newman (1961) defines a Re-number with the exit-velocity u, theradius of the coanda-tube R, the kinematic viscosity ν and the channel width h.Köster and Löhr (1964) use only the tube radius R .The Coanda-effect is not observed for R/d < 3.

Re =²2

²νRhu (Newman 1961) , Re =

νuR (Köster und Löhr 1964)

Fernholz (1966) states that for R/h > 14 the channel width h has no influence.Under R/h < 7 the influence of the channel and its boundary layer is important.

Resuc. =²2

²νRdu (suction devices)

For the use in suction devices I propose the use of the slot width d because of thestrong varying channel widths and the relative small ratio R/d 4≥ .



Fig. 3. Characteristic lengths of a) coanda-generator in suction devices, b) typical experimental setup

The coanda generators in suction devices work on the lower limit of the coanda effectin a range of R/d ≥ 4, Resuc. ~ 1000 - 10000.These frontal flows can be also structured in a U-shaped form. Fig. 4 shows the case ofa laboratory suction device with a moveable lid. This flow increases the inflow velocitynear the boundaries. Flows shown in Fig. 1 b) are reversed and easier removed.

Fig. 4. U-shaped frontal vortex for a laboratory suction device

2.2. Vortism and fluidic beings

In the following part I will develop a 'vortistic imagination' of 'the flow tracks' of twotypical fluidic beings, sharks and bonitos - a small thuna kind. This imagination wasdeveloped during painting studies of these animals. It cannot replace scientific researchon these marine animals but shall create an interaction between art and sciences asmarine research, fluid mechanics, biology etc.. The sharks belong to the elasmobranchs.The thunas are member of the teleosts. U-shape or horseshoe vortex is also a common feature for divers and other fluidicbeings Make following experiment in clear water with a foot paddle. Move the paddlenear the surface. You see two strong line vortices visible by the air entrainment. As adiver you would have a better sight of this phenomen

d

3 a) 3 b)

dh

U

URR

Moveable lid

U-shape Coanda generator

U-shaped Frontal inflow



This vortices are generated by the flow around the finedges. My idea concerning the propulsion of this is asfollows. The long side vortices of the horseshoe vasteenergy but also accelerate the fluid to propulse the'fluidic being'. Fluidic beings that depend on economiclong distance swimming have to minimize theselosses. These fish are for example a) bonitos, macrelsof the teleost group or b) sharks of thecharcharhinidae group. The fins of group a) (bonefish) are of lunatic shape. The fins of group b) manymembers of the elasmobranch group, sharks, are ofmore or less asymmetric form. This tail shape is alsocommon for sturgeons. Sharks of the lamnidae groupdeveloped nearly lunatic tails, Lindberg (1974) .

Fig. 5 Paddle-vortex

The front view of these animals reveals also differences. The fish with lunatic tails havean elliptical front cross section, Fig. 6. The front section of sharks is of a triangularform, Fig. 7. The breast fins of normal fish can be pressed to the body. The breast finsof shark are more rigid and cannot be pressed to the body. Sharks swim therefor withpermanent lift by this wing like fins. The flow pattern around a moving shark will bedifferent from the pattern of a moving thuna of comparable size or of comparablecharacteristic Reynolds - or Froude - number .

Fig. 6 Fin shape and cross section for bonitos or thunas



Fig. 7 Fin shape and cross sections for a 'typical' shark

The flow around a thuna is divided by sharp spoilers before and on the middle of thefin. These spoilers seem to divide the flow in a upper and a lower part. Fig. 8 a shows asketch of a bonito tail. A possible flow field around the tail is sketched in fig. 8 b. Thefin stroke is to the left and is symbolized by the small fish. Left/right is understoodlooking in the direction of motion.

Fig. 8 Bonito fin a) side and top view b) flow structure

Fig. 9 shows the 'flow track' of a bonito. The flow around the left/right body side of thefish is accelerated by a tail stroke to the left/right and concentrates in two line vortices.The fluid of the upper and lower body side is accelerated separately, Fig. 9 a.In a front view the flow fields of these strokes are of a bipolar kind, Fig. 9 b. The linevortices of the left/right strokes can be joined by alternatively joining the upper andlower line vortices. The bonito has a vortex track of two line vortices of opposite senseof rotation, Fig. 9 c.



Fig. 9 Flow structure of a swimming bonito, a) seperated flow around upper andlower body sides, b) bipolar flow structure, c) propulsion vortex lines.

The flow track of a shark is of different kind. The shark uses only one line vortex witheach stroke. Fig. 10 proposes a flow structure with one line vortex originating from thepropulsion fin, Fig. 10 a), b). This vortex can be connected to the trailing vortices of thebreast fins, Fig. 10 a),c) . The flow track of a shark is shown in Fig. 10 d). Thisasumption bases on the asymmetric form of the sharks fin and the typical 'cut' in the tailfins upper part.These 'vortistic' imaginations lead to the idea of a single and a double vortex linepropulsion method for fluidic beings. The being as a whole creates a typical vortexsystem. Each vortex system gives different ways to reduce drag. This system is also justpart of the beings total 'concept'. Elasmobranchs (sharks) are different in the musclestructure compared to teleosts fishes. The shark also uses a special skin. The term 'sharkskin' became synonymous with a low friction surface. The bonito itself is a lowresistance body. It is compared to profiles, Hertel (1963). My guess is that theinteraction of body and fin vortices with propulsion vortices is important andcharacteristical for the movement of many fluidic beings. The interaction of fin vorticeswith tail vortices is also observed in submarine dynamics, Burcher and Rydill (1994).



The fore planes interact with the after planes and influence the neutral stability point ofthe ship.

Fig. 10 Flow structure of a 'typical' shark

A more scientific view on the movement of aquatic fluidic beings is described in thebook 'Fish locomotion', Blake (1983). The movement of a 'ground' shark, a dogfish, isdescribed as an anguilliform propulsion mode. The whole body is moved in a propulsivewave. This mode is named after the eel, anguilla.The bonito moves in a thuniform mode. The fish moves mainly the tail. The bodyanterior of the tail shows nearly no lateral movement.

3. RÉSUMÉ

What is the difference between any scientific, for example a bionical, biological orfluid-mechanical point of view compared to an inventive, imaginative or more artistical-a painters- point of view towards the same things, the nature, our mind and itsrestrictions. The clue to this question is hidden in the restrictions. The artist is lessrestricted in the way he works, obvious disfunction, nonsense and many artisticdegrees of freedom are 'allowed'. But the perception of the artworks is dominated bythe restriction of the public. The scientific way is different. A scientific publicationmust fullfill a certain degree of scientific rules and a high degree of function. Theperception of the scientific communitiy is less restricted. The assumption is that ascientist can either understand, reject or develop further new scientific ideas. But thesenew ideas must accept permanent proofs. This disfunction / function criterion betweenart and science is described by Bierens (1999). But this criterion shows that he looksfrom the scientific side. Let us apply this criterion to this paper. The vortism of suctiondevices has at least industrial function, is patented or applied for patent. The vortism of



fluidic beings is an unproofed speculation generated by fish paintings and drawings.The pictoral art of vortism cannot be presented in a semi-scientific basic-art publicationlike this. But we can make an artistical transfer for science and propose the use ofcircular or linear frontal-vortex generators, compare Fig. 2 a), b) in a barotropic turn-table experiment at the bottom (or the vertical walls) to simulate frontal dynamics in arotating system. A appropriate turn-table with a high Ekmann layer for such anexperiment is described in Chabert d´Hieres et al. (1991). It should be possible to blockand steer the coastal current of this experiment. It should also be possible to create asource sink vortex with frontal dynamics near the bottom.

An aim of basic art is to find functions and pictures interacting with the results of suchexperiments. And this is comparable to the relation of science and art.

4. REFERENCES

[Beuys J., 1976] Ich durchsuche Feldcharakter; In: ‚Soziale Plastik‘; p. 121; EditorsHarlan et al.; Achberger Verlagsanstalt, Achberg ; ISBN 3-88103-011-5[Bierens, C., 1999] Sculpture of a Particle Accelerator; Katalog Formule 2 Exhibition;p. 110 -115; Künstlerhaus Bethanien; Vice Versa Verlag; Berlin; ISBN 3 932 754 05 0[Blake, R.W., 1983] Fish locomotion; Cambridge Univ. Press.; Cambridge;ISBN 0 521 24303 3[Burcher R., Rydill L., 1994] Concepts in submarine design; Cambridge UniversityPress;p. 180; ISBN 0 521 41681 7[Chabert d´Hieres G., Didelle H., Obaton D., 1991] A laboratory Study of Surfaceboundary Currents: Application to the Algerian Current; Journ.of Geophys. Res.; Vol96; p. 12.539 - 12.548[Coanda H., 1932] Procédé de propulsion dans un fluide; Brevet d’Invention Gr. 6 Cl .2; No. 762688, République Francaise. [Fernholz H.H., 1966] Zur Umlenkung von Freistrahlen an konvex gekrümmtenWänden, TU Berlin, DLR Bericht 66-21[Hertel, H., 1963] Struktur Form Bewegung; Mainz[Köster H., Löhr R., 1964] Untersuchungen der Umlenkung eines ebenen Strahlesdurch einen Kreiszylinder (Coanda-Effekt); Institut für Aerodynamik der DFLBraunschweig; DFL Bericht 64/30[Lindberg, G.U., 1974] Fishes of the world; John Wiley & Sons, Chichester,ISBN 0 470 53565 2[Newman B.G., 1961] The Deflection of Plane Jets by Adjacent Boundaries – CoandaEffect ; In: Boundary Layer and Flow Control; Ed. G.V. Lachmann; Pergamon Press;London[Recknagel Sprenger Schramek, 1999] Taschenbuch für Heizung + Klima Technik2000; Ed. E.R. Schramek; pp. 1439 – 1442, 1638 – 1656; Oldenbourg V.; München;ISBN 3-486-26215-7

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Vortism a Basic Art - ploland.deploland.de/Gruku-PDF/Scart-Vortismus.pdf · jets can be free, swirling or wall jets, Recknagel Sprenger (RS) (1999). A use of vortistic iconography