A modified model of a liquid nonlinear oscillator is offered. Earlier, this model was used to describe the swinging of bluff constructions, under the action of whirls forming the Karman chain. In this paper, the model is applied to describe the interaction between two whirled traces behind neighbouring bluff bodies. It is shown that the model effectively describes traces behind bluff bodies closely located to each other. It is meant that coefficients, showing relations between oscillators, are properly selected.