Session K.pdf - Clarkson University

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Indexes "n" and "m" are nature and model accordingly.Thus, at observance of a condition (3) similarity of pictures of ice destruction in theplan will be provided.It is shown, that at geometrically similar picture of ice destruction in the plan, the moduleof ice destruction resistance recalculationλR=RRndmd=nm( А L ) ( А / L ) = λ λ,z / m z mp A zwhere λA– scale of an ice cover destruction energy.zThe analysis of natural researches of physicomechanical characteristics of an ice cover[2 … 6, etc.], and also experience of modeling of ice in ice pool has shown, that the centralquestion of modelling is the choice of the base characteristic of ice which shouldanswer a number of requirements, and results of natural and modeling researches of icehave allowed to formulate these requirements:- to describe behaviour of ice under loading as full as possible;- to suppose direct measurement in natural and modeling experiments;- to be not subject to scale effect.As a result of the analysis it has been established, that energy of destruction meets therequirements to the base characteristic of ice at modeling and consequently can be acceptedas this base characteristic at development of criterial ratio and modeling experimenttechnique in ice pool.Energy of destructionA ziice plate in a zone of contact to the case. Anddepends on mechanical properties of ice and geometry of anis the most full characteristic of mechanicalproperties of an ice cover from the point of view of destruction by ships, coveringin an integrated kind all stages of destruction from formation of cracks up to a fullbreach. Application of this criterion "smooths" some discrepancies in modeling separatestages of destruction. For definition λ there is no necessity to know value forR dA zeach kind of a configuration of ice plates in a point of contact. It is required to knowonly the relation (scale) destruction energies of an ice cover of a nature and modelλ which at similar geometry depends only on properties of ice. Therefore at experimentaldefinition of λAit is possible to use results of tests of ice plates of a variouszconfiguration, for example, infinite or a semiinfinite in the plan. The resulted dependencesdo not contradict the classical theory of modeling [6], since at performance of itsrequirements =λ3 however they allow to expand search of ice model. So, for exam-λ Rdple, to receive ways of tests results recalculation for nature for the set model of an icecover.One of them is the model of fresh-water ice received in development pool. Natural icepossesses increased bend durability, what the classical theory of modeling demands.Therefore the opinion on impossibility of its application is widely distributed as modelof an ice cover. The idea of use of natural ice at modeling resistance of destruction will372A ziA zi
consist in indemnification of the increased durability by smaller thickness of an icecover. It is possible to allocate the part of ice resistance connected to destruction of iceexperimentally. For a nature, resistance of destruction is recalculated on the dependencesreceived with use of the theory of similarity and dimensions [2, 5]:R4 3 −1 3 3 2= ; υ n = λ υm; hn= λ λЕ = λ hm,n 3 md λ R dwhere λЕ– the relation of modules of elasticity of natural and thin fresh-water ice.For check of an opportunity of such modeling in ice pool tests of a scale series of the icebreaker of project É-47, the ice breaker of the project 1105, the international model ofR-class and others have been carried out. Scales of models varied from 1:13,5 till 1:50.Results of tests have shown satisfactory convergence with the natural data. Recalculationof resistance for a scale series of ice breaker R-47 has not revealed significant scaleeffect. Besides satisfactory results turned out at essential reduction in labour input andcost of tests. Visual supervision, the analysis of a photo and filmings have shown, thatthe geometrical sizes of fragments of ice and their form, and also process of interactionfor courts with traditional forms is close to observable in natural conditions. This way ofmodeling is not opposed more strict, based on selection of model of an ice cover adequatematerial. However it allows to expand volume of researches with use of the inexpensiveequipment, has simple technology, and is, in essence, unique at test seminaturalmodels in open reservoirs. The resulted dependences can be used for recalculation of iceresistance from the prototype. But this way is not ideal. In particular, the parity betweengravities and elasticity of an ice plate is not kept, energy of local destruction of an edgeof ice is unsatisfactorily modeled at contortion.Searches of models of an ice cover more full satisfying conditions of similarity and possessinghigh adaptability to manufacture have led to creation of composite constructionof ice model (1071515 and 1559593).Modeling ice represents multi-row layer of polythene granules of high pressure (granularpolyethelene ice – GP-ice), in regular intervals distributed on water surface and exposedto frost on a part of the thickness (fig. 1).Fig. 1. Composite model of an ice cover:1 – particles of polythene; 2 – natural fresh-water ice; 3 – waterThe surface of water in the pool with the help of the mechanized dosing out device becomescovered by a layer of the granulated polythene of a high pressure, and then is ex-373
Page 1 and 2: 17th International Symposium on Ice
Page 3 and 4: 57.00056.000Elevation (m)55.00054.0
Page 5 and 6: (m 3 /s)50004000300020001000Hour 24
Page 7 and 8: Tailwater Elevation vs. DischargeOb
Page 9 and 10: REFERENCESBerger, R.C. and Stocksti
Page 11 and 12: consequences of the blocked up turb
Page 15 and 16: The position of the section of maxi
Page 17 and 18: The purpose of the tests was to def
Page 19 and 20: size of the flowing up particle is
Page 21 and 22: The combined usage of the umbrella-
Page 23 and 24: hτιj⎡∂(hu∂ ⎤i ) (hu j )=
Page 25 and 26: length was ≈800 m, its average wi
Page 27 and 28: Fig. 5. The ice thickness distribut
Page 31 and 32: the most appropriate automatic spil
Page 33 and 34: HPP turbines were not operating dur
Page 35 and 36: shown (Figure 4). Along the front c
Page 39 and 40: constant inclination. The channel s
Page 41 and 42: All temperatures are compared with
Page 43 and 44: Differance [ o C]5.004.003.002.001.
Page 47 and 48: Fig. 2. Grounded hummock by drying
Page 49: from each board, going from stem to
Page 53: REFERENCE1. Goldshtejn R.V., Osipen

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