Mechanical Model for Oscillating Water Column with Compressibility

Certain aspects of modeling of the oscillating water column (OWC) wave‐power device are examined, with particular reference to its behavior at representative off‐resonant frequencies. Although comparison is made with a particular study incorporating the use of compressible flow equations for the air column, this work uses a simple mechanical analog that dispenses with the thermodynamic equations and arrives at similar results. Bearing in mind that the compressible flow study was based on quadratic damping and this one is based on linear damping, the differences when the two results are compared on an energy basis are remarkably small. The compression is made possible by the calculation of an equivalent linear damping coefficient, for the model developed here, from the quadratic damping used elsewhere. The details of the conversion are also provided. For certain studies, it is therefore proposed that the mechanical analog may be used to simplify programming and facilitate evaluation.