Kite networks as metamaterials
2016
"High-Wind" as first celeb-promoted AWE buzzword  
Mar 16, 2016  M19848   Dave Santos

What AWE gives us is a distinctly superior wind resource; more powerful, more constant, and higher than wind towers reach; but what to call it? We have seen many naming-variants of the upper-wind resource come and go-  high-altitude-wind, upper-wind, highest-wind, etc. All were weak semantically, but now Bill Gates has dubbed our realm "High-Wind", and its the most clear concise term yet. Why didn't we think of it? The dude is already making a mark, and may even unfold as a very hands-on AWE developer; one of us.

It did not exactly catch-on, but Udo's "Wind Drone" coinage was a nice try. A similar linguistic chore has been to name the new aerospace field of vast crystalline arrangements of kite sails and string. These are new theoretic forms of metamaterial at megascale, so "megametamat" comes to mind, maybe no better than "airborne lattices" (or "polymer airborne lattices" (PAL. polyairlat, etc)). "KiteMatter" is perhaps too broad. Suggestions welcomed. A good name catches fire by viral buzz. High-Wind has suddenly gone viral by a top-celeb boost, and its a good technical term as well.

Broad technological progress only proceeds at our ability to talk about it clearly, by word-making as necessary.

Experimental realization of an aero-lattice of Magnus rotors as
a topological metamaterial           29 Aug 2016     M20559   Dave Santos


There is ongoing convergence of the engineering science of AWE with topological metamaterials. Starting in the 1980's, from the World Kite Museum's specific focus on cellular kites, trains, and arches, and sources like [van Veem, '96], understanding of "kitematter" in kite culture has evolved in parallel with the science of metamaterials. Multidisciplinary study shared on this forum over the years, to master the essential cross-domain concepts, is paying off in a final comprehensive integration of kitematter to metamaterial theory. 

In the closest similarity case yet to our theoretic and empirical understanding of kite lattice potential as an AWES basis, here is a benchtop (macroscopic) realization of a hexagonal kagome lattice of gyroscopes, perturbed by puffs of air. We understand all aero-rotors as inherently gyroscopic, and the common gyroscope as a Magnus rotor in flowing media. Its uncanny how perfect the topological correspondence is of this metamaterial theory and experimental work and our documented visions for AWES kitefarm lattices on the same principles. A functional distinction is that in AWE we intend to tap the coherent edge states for power systematically.

metamaterialmetamaterialIMAGE will show:

Experimental realization of an aero-lattice of Magnus rotors as
a topological metamaterial 

M20562    Joe Faust   Aug. 29, 2016

PTO at the directioned waveguide edges!  Their study realm does seem to invite fellowship with the 2-D lattice AWES domes.  Be ready to see edge resultants in 3-D matrix AWES bodies; couplings (tethers) and wings enmeshed (rotors, turbines) may be excited by controlled interaction with the wind to give coherent edge dynamics that may be energy mined.    Nice find, that paper and its references.

Experimental realization of an aero-lattice of Magnus rotors as
a topological metamaterial 

M20563    Dave Santos   Aug. 29, 2016
Yes Joe, what is especially paying off is our relentlessly obsessive linguistic exploration of observed kite dynamics matched to modern search, to early-identify the parallel progress in AWES and metamaterial science. So we seem to have spotted these metamaterial-kitematter connections first, from the kite-tech side, before the metamaterial mainstream noticed kite-lattices.

The coolest part is that we inherit into AWES theory a bounty of formal mathematical science in metamaterials, so we don't have to reinvent the wheel to characterize our kite-lattice designs as metamaterials. Instead, we can look forward to top metamaterial scientists to validate (or not) kitematter conformance to their technical criteria.

A clarification is that while the gyroscopes in the novel metamaterial reported are crude Magnus rotors, we include every kind of HAWT-VWAT rotor variation as potentially applicable; let the best rotors win in comparative simulations and testing...

Experimental realization of an aero-lattice of Magnus rotors as
a topological metamaterial 

M20570    Dave Santos   Aug. 30, 2016

Further notes:

- Latticed gyroscopes in the experimental set-up were suspended from springs, which made them quasi-airborne and reactive to puffs of air just as flying kite Magnus rotors are.

- Lets dub our new class of metamaterial, "aerometamaterial", "aerodynamic metamaterial", or "aeroelastic metamaterial", after the example of "gryroscopic metamaterial". "Aeromet" or "AM" would be short forms.

- Our PTO networks will operate by other modes than the edge-mode introduced. Each rotor of ours could have its own PTO line directly down to the anchor-field surface. Our Edge PTOs could absorb the wave energy directly, rather than pass it around.

- WECS that operate by oscillation, by tacking or shunting, in fact rotate in phase-space as dynamical systems, so the same basic theoretic math applies as in the rotary (gyroscopic) cases.

- There is a wealth of specialized references cited by the paper that we had not seen buried in general topological metamaterial research, which is a very busy field lately, with many branches. It will pay off to follow all these new leads.

- Lets not overlook considering chiral (left or right handed) units in opposed pairs as bosonic, while a single rotor is fermionic. Just as a tuning fork, or a bird, or Dabiri's VAWTs, or our vocal cords, are all opposed pairs, this will be the pattern for many cases of rotors. Even the canonical propeller aircraft works as a double-rotor, as the chiral propeller opposes the entire airframe in equilibrium.

- A distinguishing feature of our aeromet kitefarms will be the 3D layered structure, with each 2D layer having its distinct role. For example, the top layer might be a lifter layer, then a WECS layer, then a PTO and statc tether layer, then an anchor/groundgen layer.

- Inventive aspects of these concepts have emerged on the AWES Forum, ongoingly assigned to the Open-AWE_IP-Cloud, as well as any new aspects presented here. Anyone who contributes aeromet art on this basis is recognized as an co-originator, under CC principles. Under our strong cooperative R&D ethos, lets also duly honor the vital role of key mainstream metamaterial scientists.
"Test-first"* System Identification Method in Aerospace Engineering    M20619  Dave Santos      Sep. 5, 2016
Best practice in creative AE starts by rough-and-ready heuristic empiricism that follows the resulting data trails to high-value goals. Definitive system specifications naturally follow a posteriori. System Identification is the finding of a correct formal model by data-driven experimentation.

A representative definition of System Identification in AE by Dr. Majeed Mohamed, NAL Bangalore-

"Aircraft system identification is the process of determining an adequate mathematical model of aircraft system, with unknown aerodynamic parameters which have to be determined from measured flight data. The accurate knowledge of aerodynamic parameters is very essential for controlling the aircraft system dynamics." 

Over a decade of test-first AWES experimentation in open-AWE by KiteLab Group, kPower, and others, led to the Kitematter-as-Metamaterial System Identification. The opposite approach has been to pre-define untested AWES architectures that will fail rather predictably when finally tested.

----- references ------


"Test-first"* System Identification Method in Aerospace Engineering   
Sept. 6, 2016  Dave Santos   M20623

A few more comments on AWES system identification-

Every AWES developer does some sort of system identification, but model quality varies greatly.

The most popular yet partial and misleading identification is to invoke the "blade tips only" of a conventional wind turbine as an AWES model. This completely overlooks that AWES practice far more dynamic, launching and landing regularly, and even operating in a separate higher airspace. Crosswind harvesting motion is about the only crucial equivalence of the blade-tip model. How ironic if economically optimized AWES design turns out to be more like a turbine rotor with the tips cut off, if low L/D unit-kite energy is cheap enough. The data will tell eventually.

By contrast, the "AWES as metamaterial" model grows from the common assumption of a kitefarm made up of many identical units, since a practical unit-kite, like a unit-solarcell, is far smaller than a unit-powerplant scaled to power cities. So the "brush" topology of single-line unit-kites in kitefarm form is a poor metamaterial, since its based on the HAWT kitefarm topology of each WECS unit on a single tower. The "blade-tips only" model is a very limited abstraction.

Once it is known that metamaterial science applies to AWES design, a large well-developed mathematical toolbox is available to optimize the kitefarm far beyond the blade-tip model. Optimized "kitematter" metamaterial promises to operate coherently with greater intensity, as one control process, as kitefarm airspace becomes layered with interconnection networks aloft. Further, its more apt to engineer backwards from the ~17TW global demand for sustainable energy using a metamaterial approach.

Here is a nice overview of System Identification science and art-

http://users.isy.liu.se/en/rt/ljung/seoul2dvinew/plenary2.pdf
Re: Mooring Dynamics      /Sep. 6, 2016.   M20626      Dave Santos

Thanks JoeF.

Engineered sea mooring dynamics is a very close similarity-case for engineered moored kite units, including staked-out multi-line mooring configurations approximating unit lattice-kite forces within coherent lattice-waves. An object moored to relatively fixed media is an excitable spring-mass harmonic system in moving media. Moored power harvesting buoys are particularly close analogs to proposed kite metamaterial cells.

How wonderful to find so much existing data-applicable engineering mathematics for ongoing AWES system identification and comprehensive equations-of-motion.

More Seismic-Metamaterial Progress (kite-lattice similarity-case)
M20635  Sept. 11, 2016    Dave Santos


The recent paper linked below has drawn lots of fresh attention to the potential of large-scale seismic metamaterials. The same fundamantal overall metamaterial theory is proposed by kPower to apply to suitably designed large energy kite lattices, but in the kite case the idea is to create coherent lattice wave pumping with wind, while in the seismic case the idea is to damp or guide ground waves by an engineered lattice structure.

It should not be long before the AWE-metamaterial paradigm gains attention, if we can convincingly demonstrate the criteria are met in a iso-mesh dome topology. We already know how lattice waves naturally emerge in kite trains, such that traditional Chinese centipede kite train design incorporates an aero-mass damper pair on each unit-cell.

In both macroscopic metamaterial cases the unit-cells are analogous to electron-hole lattices in semiconductor design, and the phonon energy quanta are emergent quasi-particles in the lattices.*


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* Electrons have been recently determined to be quasi-particle composites, resolving longstanding theoretic contradictions-



More Seismic-Metamaterial Progress (kite-lattice similarity-case)
M20638  Sept. 12, 2016    Dave Santos


A common descriptive nomenclature is essential to engineering practice, hence an early linguistic emphasis in innovative fields to create standard technical terms. In the paper featured here  [Miniaci et al] is proposing the same general concept as we arrived at to characterize the megascale 3D metamaterial kite lattices  that have been variously labeled here for the last few years. Miniaci's general metamaterial class name clearly encompasses our airborne metamaterial concepts, including the strong 3D megascale assumption. All large cellular kites and regular kite arrays fall in this class-

"3D Large-Scale Mechanical MetaMaterials (LSM3 )"

Its not predictable just what metamaterial class term will take hold (MegaMetaMat?), but it will likely be concise wording, maybe a clever acronym, but not have an odd-format character like the cubic exponent above. Its an exciting validation that at least we are sure we are all talking about the same general thing, and that the core metamaterial idea, explicitly expressed, may have originated here.

More Seismic-Metamaterial Progress (kite-lattice similarity-case)
M20639  Dave Santos     Sept. 12, 2016


Apparently there are many more metamaterial references to find with close parallels to enery kite lattice dynamics. Here's a Harvard example to build on-

Re: Ivy League Aeroelastic Metamaterial Research
Joe Faust   Sept. 12, 2016


Harnessing fluid-structure interactions to design self-regulating acoustic metamaterials 
Filippo Casadei and Katia Bertoldi

---In AirborneWindEnergy@yahoogroups.com, <santos137@yahoo.com> wrote :

Apparently there are many more metamaterial references to find with close parallels to enery kite lattice dynamics. Here's a Harvard example to build on-

Re: Ivy League Aeroelastic Metamaterial Research

M20641  Dave Santos   Sept. 12, 2016

Thanks Joe.  Providing a reference not just with its link, but also with its title and authors is better-searchable.

Noting that "moving media" is the latest scientific catch-all term for what was variously and often imprecisely called fluid-dynamics, hydrodynamics, and aerodynamics. Also, a reminder that "acoustic" in metamaterial science applies to large-scale oscillations of media at infrasonic  frequencies, and also ultrasonic frequencies we don't hear, but all are on the same linear spectrum of all periodic mechanical motion.

Here's a (non-Ivy-League) paper in the same vein. One can see the emergence of "lift" from a new perspective. Italians are all over this subject. After all, Pythagoras, the father of harmonic science, lived on the Italian peninsula (Croton), even if he was Greek.

Theoretical and Numerical Modeling of Acoustic Metamaterials for Aeroacoustic Applications

Department of Engineering, Roma Tre University, via Vito Volterra 62, Rome 00146, Italy



 Re: Megalifting by Kite as an early AWE commercial service

M20660   Dave Santos   Sept. 15, 2016

In fine follow-up to Song's lateral array, here's Will Rock's amazing stacked kite lifting patent filed in '65, marking a technological midway between the Golden Age of Kites and our time, fifty years later.  A perennially advanced AWE scaling paradigm is evident in this periodic lattice of modular balloons and simple sails. The detail of placing albacore aerostat lift at the LE, and simple balloons at the TE is a brilliant combination of optimal L/D function and lower cost. Only a bit of LTA lift to get the sails started up is needed. Two side taglines are an essential means of passive stabilzation. The log tackle is consistent with standard yarding,  while this is a pure-lift  AWE technology that would work with an incredible variety of tackle and applications. 

Lets hope Rock yet rocks. A hybrid energy kite metamaterial based on these cases could be dubbed "Rock Song" :)  Rock's expired patent put a lot of key kite lifting art in the public domain*. Under our open-AWE fair IP ideal, the IP-Cloud would still seek to compensate him or anyone who makes a serious contribution to AWE, no matter the vagries of patent law. Song's original contribution may be along the lines of a kytoon arch for AWE, although barrage balloons were close antecedents.

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* We want to be able to cite enough clear prior art for core AWE tech to be completely open for personal and small business use.

Kite logging

Cloud-like Aircraft Concept
M20661   Dave Santos    Sept. 16, 2016

A new sort of aviation seems possible by building on our ever-increasing kite knowledge.

Kite-based topological metamaterial lattices have the potential to develop into vast cloudlike flying structures. They could use windshear for dynamic soaring (DS) and/or distributed propulsion units to maintain flight. The concept of soaring would be expand from single units to tethered wing-pairs, and now to kite-glider lattices as a whole. In theory, with good enough wing units and suitable wind gradients, the internal DS forces could sum to enable windward flight.

From a distance, such aircraft could look like diffuse clouds of patterned light, smoke, or bird flocks, with unit sails as small as birds or as large as soccer fields. Large-scale blob-like flying structure could also harvest wind energy, lift tremendous payloads, and interface with the ground many ways. Cloud-like blobs might fly out from a few mass production centers to sites anywhere in the world.

Open-AWE_IP-Cloud