A series of wind tunnel tests were carried out to determine the effect of shark scale-based vortex generators (SSVG) on a NACA 0015 symmetrical airfoil’s aerodynamic characteristics. Three different sets of SSVG with varying geometrical parameters, such as chord length, amplitude, and wavelength, were designed and fabricated using 3D printing. The SSVG models were blended to the baseline NACA 0015 symmetrical airfoil. The wind tunnel experiments were performed over the test airfoil mounted with different sets of SSVG at various angles of attack, ranging from 0° to 24° in increments of 3°, and operating in the range of Re = 2 × 10⁵. The results revealed that the SSVG blended test airfoil reduced the drag and increased the maximum coefficient of lift (C_Lmax), thereby enhancing the overall aerodynamic performance. The SSVG offered noteworthy aerodynamic benefits by effectively altering the flow and causing significant spanwise variation in the flow properties. Additionally, attempts were made to identify the optimum chordwise location to blend the SSVG for effective use.

High-speed vehicles traveling in a tube with pressures similar to those experienced by aircraft at their maximum altitude are presented. Although the concept resembles Hyperloop, the pressure level investigated here is much higher and safer than that suggested by Hyperloop, and, therefore, the system design is markedly different. Calculating a vehicle’s aerodynamic performance in the initial design stages requires low-budget computational tools to enable iterative design processes. This study presents an algorithm for rapid flow-field prediction based on a one-dimensional Reimann solution, including viscosity and heat transfer effects. The flow-field is divided into near- and far-fields, where the near-field represents the solution directly around the vehicle. The far-field demonstrates the impact of the vehicle’s motion on the vehicle’s flow-field upstream and downstream. Two-dimensional URANS models are compared to the current numerical scheme. The developed algorithm analyzes the flow-field and the propagation of pressure waves along the tube to simulate the vehicle’s movement. The one-dimensional model shows the robustness and predictability of the near and far flow-fields. The results from the developed scheme provide good agreement, with less than a few percent deviations, compared to CFD simulations but with significantly lower computational resources.

Reynolds-averaged Navier–Stokes equations are used to simulate a practical scramjet inlet geometry using the shock-unsteadiness modified Spalart–Allmaras (SA) turbulence model. The geometry consists of fore-body ramps, expansion corners, and inlet ducts. The focus is to study the impingement of the cowl shock on the opposite wall boundary-layer. The resulting separation bubble can lead to blockage and inlet unstarts. The shock-unsteadiness correction is employed and is found to improve the computational fluid dynamics (CFD) prediction of flow separation in shock/boundary-layer interactions. The shock-unsteadiness parameter is calibrated against available experimental data of canonical flows, and the predicted flow-field is analyzed in detail. A large separation bubble size normalized to the upstream boundary-layer thickness of 4.6 is observed in the interaction region. Across the reattachment region in the interaction region, a peak value of wall pressure is observed. The inlet performance parameters are also calculated. The total pressure losses of 62% are observed across different shock waves, with an additional loss of 15% due to viscous boundary-layer effects.

The Hyperloop system offers revolutionary transportation, aiming for near-sonic speeds in a low-pressure environment. The aerodynamic design challenges of multiple vehicles in a confined tube remain largely unexplored, particularly regarding vehicle spacing and suspension gaps. This study investigates a jet-propelled, multi-vehicle Hyperloop system using Reynolds-Averaged Navier–Stokes (RANS) equations and the $k-\omega$ turbulence model. Analysis of suspension gaps and vehicle spacing on drag and thrust revealed that suspension gaps cause significant jet deflection, reducing effective thrust and increasing drag. It was found that vehicle suspension, with a 75 mm suspension gap, increased drag by 58% at Mach 0.7 compared to the unsuspended configuration. Meanwhile, smaller vehicle spacing ($X_v=0.25L_v$) reduced the drag by up to 50%, enhancing system efficiency. The results emphasize the need to address the effect of jet deflection and optimize vehicle spacing for maximum energy savings. These findings offer valuable insights for enhancing aerodynamic performance in multi-vehicle Hyperloop systems.

Reynolds-averaged Navier–Stokes equations are used to simulate a practical scramjet inlet geometry using the shock-unsteadiness modified Spalart–Allmaras (SA) turbulence model. The geometry consists of fore-body ramps, expansion corners, and inlet ducts. The focus is to study the impingement of the cowl shock on the opposite wall boundary-layer. The resulting separation bubble can lead to blockage and inlet unstarts. The shock-unsteadiness correction is employed and is found to improve the computational fluid dynamics (CFD) prediction of flow separation in shock/boundary-layer interactions. The shock-unsteadiness parameter is calibrated against available experimental data of canonical flows, and the predicted flow-field is analyzed in detail. A large separation bubble size normalized to the upstream boundary-layer thickness of 4.6 is observed in the interaction region. Across the reattachment region in the interaction region, a peak value of wall pressure is observed. The inlet performance parameters are also calculated. The total pressure losses of 62% are observed across different shock waves, with an additional loss of 15% due to viscous boundary-layer effects.

This work investigates how the vehicle-to-tube suspension gap governs compressible flow physics and operating margins in Hyperloop-class transport at 10 kPa. To our knowledge, this is the first study to apply adjoint aerodynamic optimization to mitigate gap-induced choking and shock formation in a full pod–tube configuration. Using a steady, pressure-based Reynolds-averaged Navier-Stokes (RANS) framework with the GEnerlaized K-Omega (GEKO) turbulence model, a simulation for the cruise conditions was performed at M = 0.5–0.7 with a mesh-verified analysis (medium grid within 0.59% of fine) to quantify gap effects on forces and wave propagation. For small gaps, the baseline pod triggers oblique shocks and a near-Kantrowitz condition with elevated drag and lift. An adjoint shape update—primarily refining the aft geometry under a thrust-equilibrium constraint—achieves 27.5% drag reduction, delays the onset of choking by ~70%, and reduces the critical gap from d/D ≈ 0.025 to ≈0.008 at M = 0.7. The optimized configuration restores a largely subcritical passage, suppressing normal-shock formation and improving gap tolerance. Because propulsive power at fixed cruise scales with drag, these aerodynamic gains directly translate into operating-power reductions while enabling smaller gaps that can relax tube-diameter and suspension mass requirements. The results provide a gap-aware optimization pathway for Hyperloop pods and a compact design rule-of-thumb to avoid choking while minimizing power.