The interaction effect between vaporising cylinders arranged in three different triangular configurations, under quasi-steady non-convective conditions, has been determined by employing the finite element method. The interaction effects are expressed in terms of the variation of the interaction coefficient with inter-particle separation, and the iso-density contours. It is seen that, while the interaction coefficients for all the cylinders increase with spacing, they are lower for cylinders which are surrounded by other cylinders.