CPC G01M 10/00 (2013.01) [B63B 71/20 (2020.01); B63B 2211/06 (2013.01); C09K 3/24 (2013.01)] | 3 Claims |
1. A method of ship ice resistance model experiment based on non-refrigerated model ice, comprising the following steps:
S1. determining an overall length L1, a breadth B, and a scale ratio λ of a selected ship model;
determining a size A1 of an experimental area for placing broken ice in the ship ice resistance model experiment: according to the overall length L1 and the breadth B of the selected ship model, determining the minimum size of the experimental area, further determining the size of the experimental area:
L2≥5L1,
W≥3B,
A1=WL2,
wherein, L2 represents a length of the experimental area, and W represents a width of the experimental area;
S2. determining a characteristic length of model ice:
S21. determining a target coverage ratio c of the model ice;
S22. according to the experimental area size A1 obtained in step S1 and the target ice coverage ratio c obtained in step S21, determining a total area A2 of the model ice:
A2=cA1;
S23. according to the bending theory of thin plate sitting on elastic foundation, determining a critical characteristic length Lc of the broken ice without bending failure:
wherein, D represents a flexural rigidity of ice, satisfying the following equation:
E represents an elastic modulus of ice, with the unit of Pa; t represents an actual thickness of the broken ice, with the unit of m; v is Poisson's ratio; and k represents an elastic stiffness of the base, satisfying the following equation:
k=ρwg,
ρw is the density of water, with the unit of kg/m3; and g is the acceleration of gravity, with the unit of kg/m2;
S24. determining the critical characteristic length l:
wherein, L represents a characteristic length of the broken ice, satisfying the following condition:
L≤Lc;
S25. according to the critical characteristic length l of the model ice, determining a characteristic length ln of each size of the model ice in the ship ice resistance model experiment;
S3. determining a quantitative proportion of the model ice for each size under the target coverage ratio c of the model ice:
wherein, N(ln) represents a number of the model ice with the size ln, α1, a2, β1 and β2 are coefficients, α1=1.15, α2=1.87; when the characteristic length ln of the model ice is in a range of [l1,l2], the total area of the model ice satisfies the following equation:
solving the following set of equations to obtain β1 and β2,
S4. according to the quantitative proportion of the model ice of each size under the target coverage ratio c obtained in step S3, and the total area A2 of the model ice to obtain the number of the model ice of each size under the target coverage ratio c; and
S5. determining a geometrical shape and parameters of the model ice for each size under the target coverage ratio c:
a roundness R of the model ice satisfies the following equation:
wherein, dp represents a perimeter-equivalent diameter, d represents a area-equivalent diameter, and d is equal to ln, P represents a perimeter of geometrical shape of the model ice;
an area S of the geometrical shape of the model ice satisfies the following equation:
a caliper diameter ratio Ra of the model ice satisfies the following equation:
Ra=Dmax/Dmin;
determining P according to the value of R;
determining the geometrical shape of the model ice according to P, S, and Ra.
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