In this study, unsteady low Mach number flow field and aerodynamically generated noise of 2D cavity flows are investigated. In the case of 2D flow fields, different unsteady Detached Eddy Simulation (DES) turbulence models are used to observe cavity flow field. SST k-omega with two transport equations and Spalart-Allmaras with one transport equation are used to calculate near field to take in account wall effect in which DES is used. In addition to these, different discretization algorithms and approaches are employed to calculate the flow field and to account the acoustic level. Computed numerical results for cavity flow are compared and validated with an experimental measurement of low Mach numbers for the flow filed quantities and acoustic signals. All unsteady flow fields results are used to compute a cavity noise using Ffowcs Williams-Hawkings (FW-H) Acoustics Analogy and compared with experimental data. At 500 - 1500 Hz, well agreement is observed between numerical result and the experimental data which are conducted for cavity noise.