Experimental investigation of airflow over helicopter platform of a polar icebreaker

The airwake over the helicopter platform of a Canadian Coast Guard (CCG) polar icebreaker was studied experimentally. By application of high speed particle image velocimetry (PIV) on a 1:522 scaled model of the polar icebreaker, quantitative flow filed data were obtained in several vertical and horizontal planes. Present investigation was conducted with two types of the inflow conditions: (i) a uniform flow and (ii) a simulated atmospheric boundary layer (ABL). The incidence angle (α) varied between 0° to 330° with the increment of 30°. The unsteadiness of the flow was demonstrated by calculation of standard deviation of vertical airflow velocity (σ) over the helicopter platform, which directly influences the pilot workload. It was observed that, despite having relatively the same trend in different angels of incidence, the maximum value of σ is generally higher in the case of simulated ABL. It could be attributed to higher velocity gradients in oncoming flow associated with the simulated ABL inflow condition. Additionally this investigation showed that, in both inflow conditions, incidence angles of 0° and 300° were associated with the highest values for σ.