Vertical Motion of Neutrally Buoyant Floats

Abstract

Abstract The vertical motion of a neutrally buoyant float is determined from the solution to the nonlinear forced harmonic oscillator equation originally set forth by Voorhis. Float response to forced vertical oscillations is characterized by the response ratio, r = ξr/ξw, where ξr, is the vertical displacement of an isopycnal relative to the float, and ξw is the vertical displacement of an isopycnal relative to its initial equilibrium position. For isopycnal displacements with frequencies much less than the resonant frequency of the float, the goat can be considered to be in near dynamic equilibrium with the forcing, and r is a function of the relative compressibility between the float and seawater, s = γf/ γw, and the normalized buoyancy frequency N = N/Ω, where Ω is a characteristic float frequency defined by Ω2 = gξw[1 − (αfαw−1)]− 1, where αf, αw are the coefficients of thermal expansion of the float and water, respectively. For the new dynamic equilibrium case, data obtained from a float deployment ...