Opportunities and restrictions on the use of zone rans-iddes approach to a fan noise calculation

An analysis of the possibility of applying a method developed by the author's zone RANS-IDDES method, which includes a scheme with a local imposition of implicit to the problem of calculating the noise of the turbofan engine fan. The estimates of the required mesh power are presented to use the Wall Modeled LES on the 1/4 chord of the rotor blades near their rear edges, which made more than 600M cells. It was concluded that the impossibility of consideration of the flow in a vortex-solving formulation for border layers on the rotor blades from their front edges for current and promising calculations. The calculation confirmed already published ideas that the zonal RANS-LES approach to the vortex resolved with the explicit and high-quality generation of turbulent content is preferable for such tasks. The importance of the qualitative description within the URANS regions near the front edges of the rotor blades, especially near the radial gap, is noted. A modification of a VSTG generator is proposed, which improves the size of the generation for the nonuniform mean field of speeds. As a result, the noise of the fan stage is obtained, which is consistent with the exploiter, both in tonal and in broadband parts.