Wavy fins are one of the most popular fins in compact heat exchangers used in the refrigeration industry. The mechanisms responsible for heat transfer and pressure drop with wavy fins are quite different when compared to plate fins. The wave angle, fin pitch, fin thickness, waffle size, the number of the rows of tubes, and tube pitches are the parameters that decide the performance of the heat exchanger surface. Minimal modifications of these parameters could produce significant improvement in the fin performance. A complete understanding of both heat transfer and pressure drop mechanisms with wavy fins is very important for heat exchanger designers. This work deals with thermal-hydraulic performance of wavy fins having one, two, three or four rows of tubes. The Reynolds number, based on the hydraulic diameter of the channel of a heat exchanger, is always inside the laminar regime, ranging from 200 to 2000. Heat transfer and pressure drop mechanisms are identified. The approach is numerical, using Computational Fluid Dynamics. A conjugate heat transfer calculation with coupling walls and periodic conditions was implemented. The impingement flow on surfaces, boundary layer development, and horseshoe vortex in front of the tube were the identified heat transfer mechanisms, with the first one playing a major role. Among the models studied, the model having one row has the largest heat flux, with the bott om side of the fin having a better performance than the top side. The heat transferred by each tube was investigated, and the second row of tubes was found as most effective when compared to the rest.