Abstract: A four-wheel rudimentary landing gear is studied numerically by unsteady RANS (URANS), detached eddy simulation (DES) and delayed detached eddy simulation (DDES) based on the Spalart-Allmaras turbulence model. The surface sound pressure level and sound pressure spectra are calculated using the obtained unsteady flow field. The 3 methods cost approximately the same time, with URANS slightly lower than the other two. DDES uses slightly less time than DES since it retains RANS mode in attached flow region. The investigation shows that URANS can give reasonable results in the attached flow region but cannot describe correctly the flow pattern in the detached flow. Both DES and DDES can describe the steady and unsteady properties in the flow around rudimentary landing gear. DDES is slightly superior over DES, and DES can also give reasonable results since the flow around the landing gear is a massive separated flow. The results prove the feasibility of DES type methods in massive separated unsteady flow field and aerodynamic noise prediction for landing gear, and can be used in the study of landing gear noise reduction.