Direct numerical simulation of flow around a heated/cooled isolated sphere up to a Reynolds number of 300 under subsonic to supersonic conditions

Direct numerical simulation of subsonic, transonic and supersonic flow over an isolated sphere up to a Reynolds number of 1000

“…Also, they investigated the fundamental characteristics of flow past a stationary heated/cooled sphere (Nagata et al . 2018 a ) and a rotating adiabatic sphere (Nagata et al . 2018 b ), respectively, at 0.3 ≤ M ≤ 2.0 and 100 ≤ Re ≤ 300.…”

“…The flow past a sphere under the compressible low-Re flow has numerically been studied by Nagata et al (2016), Riahi et al (2018) and Sansica et al (2018). Nagata et al (2016Nagata et al ( , 2018a used DNS with a body-fitted grid to investigate fundamental characteristics such as aerodynamic force coefficients, flow structures and flow regime, with a stationary adiabatic sphere at 0.3 ≤ M ≤ 2.0 and 50 ≤ Re ≤ 300. They showed that the wake behind a sphere under compressible flows is similar to that under incompressible flows (alternating hairpin vortex wake) for M ≤ 0.8, but the wake structure became a steady axisymmetric wake at M ≥ 0.95 and Re ≤ 300 (Nagata et al 2016).…”

“…They showed that the wake behind a sphere under compressible flows is similar to that under incompressible flows (alternating hairpin vortex wake) for M ≤ 0.8, but the wake structure became a steady axisymmetric wake at M ≥ 0.95 and Re ≤ 300 (Nagata et al 2016). Also, they investigated the fundamental characteristics of flow past a stationary heated/cooled sphere (Nagata et al 2018a) and a rotating adiabatic sphere (Nagata et al 2018b), respectively, at 0.3 ≤ M ≤ 2.0 and 100 ≤ Re ≤ 300. It should be noted that they imposed a fully no-slip condition on the surface of the sphere in all their simulations, even though a part of the flow condition was in a non-continuum regime (e.g.…”

Experimental investigation on compressible flow over a circular cylinder at Reynolds number of between 1000 and 5000

“…This situation is similar to the case of compressible low-Re flows over an isolated sphere. The flow characteristics of the compressible low-Re flow over a sphere have been examined by DNS and global stability analysis at Re 1000 (Meliga, Sipp & Chomaz 2010;Nagata et al 2016Nagata et al , 2018aRiahi et al 2018;Sansica et al 2018) and by schlieren visualization through free-flight tests at 3.9 × 10 3 Re 3.8 × 10 5 (Nagata et al 2019). However, there is no report on the unsteady flow properties by computational or visualization studies at Re ≈ O(10 3 ) for compressible flows, because this region is difficult to investigate through either computation or visualization due to the large computational cost or small test model with low-density conditions, respectively.…”

Eulerian–Lagrangian direct numerical simulation of preferential accumulation of inertial particles in a compressible turbulent boundary layer

“…With the developments of high-speed aircraft, compressible turbulent flows laden with particles or droplets are drawing considerable attention. For example, compressible turbulent boundary layers (CTBLs) laden with particles are commonly encountered in the mixing of fuels in scramjets (Urzay 2018), flights in sandy or rainy atmospheres (Fedorov 2013) and exhaust gas from rocket engines (Nagata et al 2018). Particles are essential for triggering compressible boundary layer transition processes (Chuvakhov, Fedorov & Obraz 2019), affecting flight performance (Li & Bai 2015), and controlling the temperature and noise of exhaust gas flow (Ignatius, Sathiyavageeswaran & Chakravarthy 2014).…”