In　this　study,　the　flow　behaviors　and　throttle　effects　of　high-pressure　air　flow　through　orifices　were　experimentally　investigated　in　a　pipe　system　and　numerically　simulated　using　Reynolds-averaged　Navier-Stokes　equations　with　the　shear　stress　transport　(SST)　k−ω　turbulence　model.　Three　orifice　configurations　with　porosities　(orifice　hole　area　to　pipe　area　ratio)　of　β　=　28.4%,　7.1%,　and　1.8%　were　comparatively　evaluated　under　four　different　inflow　pressures,　i.e.,　pin　=　1,2,3,　and　4　bar.　The　numerical　results　agreed　well　with　the　corresponding　experimental　measurements.　A　primary　recirculation　with　a　smaller　secondary　recirculation　region　was　formed　immediately　behind　the　trailing　face.　In　the　presence　of　supersonic　flow,　the　streamwise　velocity　exhibited　periodic　oscillations,　increasing　at　the　expansion　wave　and　decreasing　at　the　shock　wave　region.　The　throttle　effects　were　highly　sensitive　to　the　orifice　porosities　and　the　inflow　conditions.　In　the　β　=　28.4%　configuration,　shock　waves　and　expansion　waves　were　evident　under　different　inflow　pressures　and　alternately　dominated　the　downstream　flow,　leading　to　periodic　streamwise　temperature　variations,　with　the　minimum　temperature　reaching　−160　°C　at　pin　=　4　bar.　For　the　orifice　with　β　=　7.1%,　the　expansion　and　shock　waves　appeared　at　pin　≥　2　bar,　and　continuously　expanded　with　intensified　flow　fluctuations　at　pin　=　3　and　4　bar,　with　the　minimum　temperature　reaching　−120　°C.　For　the　orifice　with　β=1.8%,　the　impact　of　shock　waves　on　the　temperature　field　was　barely　observable　under　pin　=　1　and　2　bar　due　to　the　small　porosity.　When　pin　≥　3　bar,　similar　temperature　patterns　with　larger-porosity　orifices　were　observed　downstream　of　the　orifice　trailing　face　but　were　smaller　in　size.　©　2024　Author(s).