Application of а harmonic balance method to a calculation of the first booster stage tone noise

The results of the numerical investigation of the tone noise of the first booster stage of the high bypass ratio turbofan in the far field at approach operational conditions are presented. The investigation is performed using the frequency domain numerical method of multistage turbomachines tone noise simulation, developed in CIAM. A variant of the method suitable for the calculations in nonlinear setup is used. Calculation is performed for several blade passages in each row. The harmonic balance method for multi-tone disturbances with frequency mapping is implemented. The results of the calculations are compared with the results of the calculations in the time domain, presented in the previous paper (they were also performed in nonlinear setup) and with the experimental data obtained in the CIAM acoustic test facility. In general satisfactory correspondence is found between the data in both cases. The results can be treated as an argument for the validity of the proposed nonlinear frequency domain method of the multistage turbomachinery tone noise calculations.