Investigação teorica e numerica sobre hidrofolios delta

AUTOR(ES)
DATA DE PUBLICAÇÃO

1975

RESUMO

The linearized three-dimensional theory for a flat hydrofoil operating below a free surface is obtained. By satisfying the free surface boundary condition, boundary conditions on the foil and its wake and the radiation condition, a general expression for the velocity potencial is deduced. This expression is valid for any geometry, Froude number and depth of submergence in steady motion. After various mathematical manipulations, a suitable expression for the numerical calculation of delta hydrofoils performance is obtained. The numerical treatment is made using the collocation lifting surface tecnique, where the hydrofoil is replaced by a doublet distribution, both in chordwise and spanwise directions. The numerical integration is carry out using the Formula of arbitrary integrations limits, except the second order singularity in the aerodynamic term, treated by the Lagrangian interpolating polinomials. Several operational conditions are analized, discussed and compared with theoretical and experimental available work. It is found that the lift and induced drag for delta hydrafoils increase or decrease depending on the range of utilization Fraude number, and that the influence of the free surface over the hydrofoil characteristics decrease with increase the depth of submergence. For large aspect ratio hydrofoils the influence of free surface is less than for small aspect ratio hydrofoils

ASSUNTO(S)

massas girantes de fluidos aerodinamica hidrodinamica

ACESSO AO ARTIGO

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