Simulations of subsonic free jets can only compute noise contributions from sources connected with the large-scale structures occurring close to the potential core region and their breakdown to fine-scale turbulence (Freund,
). To account for additional noise sources associated with fine-scale turbulence in the initial shear layers and the interaction of flow with the nozzle lip, the nozzle must be included in the simulation and, moreover, the flow inside the nozzle must be fully turbulent. Previous work including realistic nozzle geometries in the simulation failed to achieve fully turbulent flow at the nozzle exit (e.g. (Uzun and Hussaini,
)). To overcome the difficulties encountered when using realistic geometries, the problem can be simplified by using a canonical nozzle with well defined turbulent exit conditions. The ultimate goal of this ongoing study is to use a round pipe with sufficient length as a canonical nozzle for direct noise computations of jets. This paper focuses on whether the flow conditions at the pipe exit can be used as well defined turbulent upstream conditions for such calculations. From this perspective the following issues are of interest: (i) the effect of the inflow boundary conditions on the length of the pipe required to obtain fully developed turbulent pipe flow (development length); and (ii) the effect of compressibility on the temperature field. The former is needed to specify the length of the nozzle for full jet calculations, while the latter is related to the correct prescription of the ambient temperature. The spatially developing pipe flow using a turbulent inflow generation was chosen for this study instead of the alternative recycling or precursor simulation techniques because it avoids introducing an undesired artificial recycling frequency, the need to impose a pressure gradient, and minimizes the computational cost and memory requirements.