Static pressure distribution in the inlet of a helicopter turbine compressor

The parallel compressor model was used to demonstrate that when the airflow into a compressor is distorted, the velocity at the inlet to the compressor will be virtually constant with consequent variations in the static pressure. Refined parallel compressor models have been proposed in which it is assumed that the compressor tends to induce a constant air inlet velocity with static pressure gradients that are in sympathy with the total pressure gradients. Four basic elements have been identified to be important for distortion measurement: 1) circumferential intensity, 2) extent and 3) multiple-per-rev elements defined at constant radius, and 4) a radial intensity element.