Synergistic Control of Supersonic Jet Flows: Numerical Investigation of Multiple Protuberance and Coanda Effect Integration

This study numerically investigates transonic jet control in a rectangular nozzle with Mach (M) = ۱ at the throat, issuing at Nozzle Pressure Ratio (NPR = P۰/Pa) = ۲.۵ (P۰ = ۲۱۰ kPa, Pa = ۸۴ kPa, T = ۳۰۰ K; fully expanded M ≈ ۱.۲۲). A two-dimensional steady RANS framework (SST k–ω, density-based implicit solver, Roe flux; CFL ramp ۰.۵ → ۲) is employed in a ۱۰۰ × ۷۵ throat-based domain with adiabatic no-slip walls and a hybrid mesh (≈ ۲.۳ – ۲.۵×۱۰۵ elements). We vary the number, placement (throat and/or Coanda flaps), and penetration depth (Pen.) of protuberances. With two protuberances (throat + flap), the system exhibits discrete deflection plateaus: Deflection Angle (DA) ≈ ۳۵ – ۳۷° (flap slot ۲۲.۵°) and DA ≈ ۶۸ – ۷۵° (slots ۷.۵° or ۳۷.۵°), with resultant-force ratio (FR/FR۰) ≈ ۰.۹۵ – ۰.۹۹. Introducing a third protuberance enables intermediate deflections (e.g., DA ≈ ۵۱°, −۵° to −۲۱°) at FR/FR۰ ≈ ۰.۸۶ – ۰.۸۹ (efficiency trade-off). Removing the throat protuberance while retaining two flap-mounted elements yields DA ≈ ۶.۵° at near-zero loss (FR/FR۰ ≈ ۱.۰). Overall, across the explored layouts, DA spans −۲۱° to ۷۵° while FR/FR۰ spans ۰.۸۶ – ۱.۰, quantifying how strategic multi-protuberance layouts expand the deflection spectrum beyond binary attachment/detachment and clarify efficiency trade-offs for integrated protuberance–Coanda control at NPR = ۲.۵.

کلیدواژه ها:

Flow Control ، Coanda Effect ، Computational fluid dynamics ، compressible flow ، Shock Waves