Perturbation techniques can provide valuable insights into flow control by identifying sensitive regions. However, performing such analyses with high-fidelity techniques, such as large eddy simulations or direct numerical simulations, can be computationally prohibitive. In this effort, we employ reduced-order modeling (ROM) of compressible Navier-Stokes equations based on the Galerkin-projection and proper orthogonal decomposition (POD) toContinue reading “Galerkin-POD Reduced-Order Modeling of Compressible Flows”
Author Archives: vilasjshinde
Lagrangian Modal Analysis (LMA)
Modal decomposition finds common use in flowfield analysis, data-driven modeling and flow control. Among the more popular techniques are proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD). Modal analysis is most often performed in an Eulerian (fixed) frame of reference using unsteady flow snapshots obtained from experimental measurements or solutions to the governing equations.Continue reading “Lagrangian Modal Analysis (LMA)”
Supersonic flow separation control using surface morphing
Control of Transitional SBLI The potential of surface morphing techniques, including passive shock control bumps (SCB) and active surface morphing, is explored to control transitional shock wave boundary layer interactions (SWBLI). In addition to reducing the size of the separation bubble, a key objective is to mitigate the low-frequency unsteadiness that can cause detrimental structuralContinue reading “Supersonic flow separation control using surface morphing”
Turbulence modeling for large eddy simulation
In large eddy simulation (LES), the large scales of turbulent motion are resolved directly, whereas the small scales that are computationally expensive to solve are modeled. The scale separation is performed either in the physical domain (space or time) or in Fourier space, which involves application of an explicit or implicit scale filtering operation, partingContinue reading “Turbulence modeling for large eddy simulation”
Shock wave boundary layer interaction over flexible panel
Shock wave boundary layer interaction (SBLI) exhibits low frequency unsteadiness, which can interact with structural modes, giving rise to detrimental fluid-structure interactions. To investigate the physics of these interactions, we perform high-fidelity simulations of transitional and turbulent SBLI over flexible surfaces. Transitional SBLI over flexible panel We investigate a full 3-D transitional SBLI over aContinue reading “Shock wave boundary layer interaction over flexible panel”
Galerkin-free reduced-order modeling for multiphysics systems
Galerkin projection of Navier–Stokes equations on proper orthogonal decomposition (POD) basis is predominantly used for model reduction in fluid dynamics. Robustness for changing operating conditions, numerical stability in long-term transient behavior and the pressure-term consideration are generally the main concerns of the Galerkin-POD reduced-order models (ROM). We develop a novel procedure to construct an off-referenceContinue reading “Galerkin-free reduced-order modeling for multiphysics systems”
Inflow turbulence generation for large eddy simulation
Digital Filtering Technique Digital Filtering (DF) is an efficient method to generate the inflow turbulence, which is an important parameter that can affect the physics of interest. In most of our supersonic LES simulations, we employ the digital filter procedure that is originally proposed by Klein et al. (2003), and later improved by Xu etContinue reading “Inflow turbulence generation for large eddy simulation”
Flow-induced vibration in sodium-cooled fast reactor
The core of sodium fast breeder reactor (Na-FBR) comprises hexagonal slender structures arranged in a very confined manner. The flow of liquid sodium through the cavities and the hexagonal structures lead to complex fluid-structure interaction. To investigate the flow induced vibration, we performed large eddy simulations (LES) alongside the ongoing experimental efforts in French alternativeContinue reading “Flow-induced vibration in sodium-cooled fast reactor”
Homogenization/macroscopic modeling
The steam generator and reactor core of a nuclear power plant comprise a large number of small tubular structures with high interstitial velocities, leading to high Reynolds numbers, for instance, Figure 1 shows the internal view of the two process equipments. High-fidelity CFD simulation of the entire steam generator or reactor core is not feasibleContinue reading “Homogenization/macroscopic modeling”
Fluidelastic instability in heat-exchanger tube bundles: theoretical model
The high-fidelity LES of the fluidelastic instability yielded vital insights into the physics of interaction between the velocity flow and a cylinder in a tube bundle. In particular, the LES flow fields exhibited the modified flow regions due to cylinder oscillations, which were in and out of synchronization with surrounding flow for increasing flow velocity,Continue reading “Fluidelastic instability in heat-exchanger tube bundles: theoretical model”
Vilas Shinde 