A deeper understanding of the effect of the swirl flow mechanism in gas turbine combustion is essential to design optimized combustors under various operating conditions. The double swirl flow arrangement has an advantage over the single swirl flow by proving better mixing and flame anchoring due to the increased shear action between the two swirl flows. The non-reacting flow characteristics of the unconfined double swirler burner are studied for various Reynolds numbers. 2D particle image velocimetry (PIV) technique with proper spatial calibration was used to carry out the experiments, and the velocity field is calculated using Insight4G software (TSI). The velocity field and the turbulence parameters such as Reynolds stress and turbulent intensity under different Reynolds numbers are analyzed, which helps to enhance our understanding of the turbulence mixing. The results show that the increase in outer swirl Reynolds number increases the radial component of the velocity; therefore, the swirl flow spread in the radial direction is increasing. Similarly, the outer swirl Reynolds number affects the turbulent parameters such as Reynolds stress and turbulence intensity. Because of this phenomenon, the spread of the flame front may occur and further to the local quenching in the worst case. © 2021, Springer Nature Singapore Pte Ltd.