Abstract: In as paper, an eddycurrent analogy and a brief sketch of required equipment are presented. Values oftorsional rigidity and shearing stresses of a prismatic bar under free torsion can be obtained experimentally to a high degree of accuracy in an instant with this equipment whether the cross-section is bounded bv a single boundary or multi-connected boundaries. The error is les than two per cent generally, as shown in Table 3- ’Hits new analogy can be used extensively to solve various physical problems expressed by Poisson’s (or Laplace’s) equation with constant boundary condition.

Key words: theory of poroelasticity, open channel flow, vegetation, secondary current, depth-averaged velocity distribution