Article
Thermodynamics
Yang Zheng, Cheng Xu, Zheng Xinghua, Chen Haisheng
Summary: The paper presents a set of new equations SCF-RANS equations to describe turbulent flow and heat transfer of supercritical fluid, taking into account the fluctuation of thermal physical properties. Various model methods for the new correlation term have been discussed for closing the equations, providing reference information for these new correlations. The SCF-RANS equations not only offer a formulation specific to supercritical fluid flow and heat transfer, but also represent the most sophisticated form of the RANS equations with consideration of all physical properties as variables.
JOURNAL OF THERMAL SCIENCE
(2021)
Article
Mechanics
Y. Marchenay, F. Chedevergne, M. Olazabal Loume
Summary: A new modeling strategy is proposed to predict the combined effects of roughness and blowing boundary conditions. Analysis of experimental data reveals deficiencies in existing roughness corrections when predicting the effect of blowing in the presence of surface roughness.
Article
Engineering, Aerospace
Yuanwei Bin, George Huang, Robert Kunz, Xiang I. A. Yang
Summary: This paper introduces a constrained model recalibration method in RANS turbulence models to address the negative impact of modifications on basic calibrations. By identifying the degrees of freedom that do not affect the basic calibrations and only modifying them when necessary, models that perform well in historically challenging flow scenarios can be trained.
Article
Thermodynamics
Yuewen Jiang, Alexander Murray, Luca di Mare, Peter Ireland
Summary: This study investigated the mesh sensitivity problem of RANS simulations by comparing two different hole geometries and seven mesh sizes under different blowing ratios. The results show that mesh convergence becomes challenging for RANS modeling, especially for fan-shaped holes.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Computer Science, Interdisciplinary Applications
Eric L. Peters, Riccardo Balin, Kenneth E. Jansen, Alireza Doostan, John A. Evans
Summary: Despite their limitations, Reynolds averaged Navier-Stokes (RANS) models are still widely used in engineering practice for modeling turbulent flows. This paper introduces a data-informed approach for improving the predictive performance of Reynolds stress models by learning components of the Reynolds stress discrepancy tensor. The proposed approach automatically generates symmetric Reynolds stress models that are Galilean and frame invariant, showing effectiveness in various turbulent flow problems.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Green & Sustainable Science & Technology
Alibek Issakhov, Perizat Omarova
Summary: This study developed a mathematical model to investigate fluid flow and pollutant dispersion characteristics in a certain quarter of Almaty city, Kazakhstan. It was found that setting barriers along the road can reduce the concentration of harmful substances in the pedestrian zone air.
JOURNAL OF CLEANER PRODUCTION
(2021)
Article
Engineering, Multidisciplinary
Sabrina Star (''Kelbij''), Giovanni Stabile, Gianluigi Rozza, Joris Degroote
Summary: A Finite-Volume based POD-Galerkin reduced order modeling strategy for steady-state Reynolds averaged Navier-Stokes (RANS) simulation is extended to low-Prandtl number flow, by varying the Richardson number to characterize the effects of buoyancy. The reduced order model successfully predicts velocity and temperature profiles in good agreement with RANS simulations, and captures local Stanton number and skin friction distribution at the heated wall.
APPLIED MATHEMATICAL MODELLING
(2021)
Article
Engineering, Ocean
Andrea Franceschi, Benedetto Piaggio, Diego Villa, Michele Viviani
Summary: This study investigates the main interaction effect of hull and propeller on the rudder inflow in a conventional manoeuvring simulator using a simple but robust approach. The modular/MMG based method describes the hull, rudders, and propellers with separate mathematical models to account for interaction phenomena. Numerical models developed in OpenFOAM for propeller-rudder interaction and two different approaches for hull-rudder interaction show improved accuracy compared to a calibrated semi-empirical model.
APPLIED OCEAN RESEARCH
(2022)
Article
Engineering, Chemical
Seung Il Baek, Joon Ahn
Summary: A large eddy simulation (LES) was conducted to study film cooling in gas turbine blades with different injection angles and blowing ratios. The results showed that the reattachment of injectant at a compound angle was better predicted by RANS simulation, while the adiabatic film cooling effectiveness was better reflected by LES, even under compound angles.
Article
Engineering, Marine
Andrea Franceschi, Benedetto Piaggio, Roberto Tonelli, Diego Villa, Michele Viviani
Summary: This study evaluated the prediction quality of a twin-shaft naval vessel's manoeuvre using CFD hydrodynamic coefficients, demonstrating that the application of these coefficients provided a good estimate of the main IMO manoeuvres. The DTMB 5415M frigate was used as a test case, which has been investigated in various research studies and international benchmark workshops.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Mathematics, Applied
Jad Doghman, Ludovic Goudenege
Summary: The primary focus of this research is the development of a finite element based space-time discretization method for solving the stochastic Lagrangian averaged Navier-Stokes equations in incompressible fluid turbulence. Convergence analysis shows that convergence to continuous strong solutions is achieved when alpha approaches zero or when alpha is fixed.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2022)
Article
Engineering, Ocean
Wanhai Xu, Haokai Wu, Mu Sha, Enhao Wang
Summary: This study numerically investigates the two-degree-of-freedom flow-induced vibrations of an elastically mounted circular cylinder pair arranged in parallel. The effects of the interaction between the cylinders on the response, hydrodynamic features, and wake patterns are evaluated.
APPLIED OCEAN RESEARCH
(2022)
Article
Energy & Fuels
Seung-Il Baek, Joon Ahn
Summary: This study investigates the effects of 36-Hz pulsations on the film-cooling flow, including streamwise velocity distributions, turbulence statistics, and temperature fluctuations. Numerical methods are used to simulate the flow, and the results are compared with experimental data. It is found that under 36-Hz pulsations, the streamwise velocity of the coolant jet is weaker, leading to instability in the flow field. Additionally, both temperature fluctuations and velocity fluctuations increase. The distribution of the results may vary with the orientation angle, but the overall trend remains similar.
Article
Computer Science, Interdisciplinary Applications
Diego Lodares, Juan Manzanero, Esteban Ferrer, Eusebio Valero
Summary: This article presents an entropy-stable formulation for the compressible Reynolds Averaged Navier-Stokes (RANS) equations and the Spalart-Allmaras closure model. The proposed model satisfies an entropy law and employs a high-order Discontinuous Galerkin (DG) approximation with discrete stability analysis. The schemes demonstrate stability and accuracy for three-dimensional unstructured meshes and different flow cases.
JOURNAL OF COMPUTATIONAL PHYSICS
(2022)
Article
Engineering, Chemical
Ye Hwan Chun, Joon Ahn
Summary: A series of numerical simulations were conducted to investigate the discharge coefficient of a stepped labyrinth seal based on its geometric parameters, and the mechanism for improving the sealing performance was studied. The results showed that the stepped labyrinth seal had a higher leakage-suppression performance compared to the straight labyrinth seal, and the discharge coefficient varied with the flow field in the cavity.
Article
Engineering, Aerospace
Sandilya Kambampati, Ranjan Ganguli
Article
Engineering, Aerospace
Sandilya Kambampati, Edward C. Smith
JOURNAL OF AIRCRAFT
(2017)
Article
Mechanics
Sandilya Kambampati, Ranjan Ganguli
Article
Computer Science, Interdisciplinary Applications
Gang-Won Jang, Sandilya Kambampati, Hayoung Chung, H. Alicia Kim
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2019)
Article
Computer Science, Interdisciplinary Applications
Sandilya Kambampati, Carolina Jauregui, Ken Museth, H. Alicia Kim
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2020)
Article
Engineering, Aerospace
Sandilya Kambampati, Scott Townsend, H. Alicia Kim
Article
Computer Science, Interdisciplinary Applications
Sandilya Kambampati, Justin S. Gray, H. Alicia Kim
COMPUTERS & STRUCTURES
(2020)
Article
Engineering, Multidisciplinary
Sandilya Kambampati, Hayoung Chung, H. Alicia Kim
Summary: This paper proposes a new methodology for computing boundary sensitivities in level set topology optimization using the discrete adjoint method. By combining local perturbations with derivatives of the objective function, boundary sensitivities can be calculated. This method avoids the smoothing or interpolation methods typically used in sensitivity calculations, improving accuracy and convergence characteristics.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Computer Science, Software Engineering
Sandilya Kambampati, Carolina Jauregui, Ken Museth, H. Alicia Kim
Summary: In this study, new algorithms for efficient function representation based geometric design using Volumetric Dynamic B+ tree (VDB) were introduced. The Fast Sweeping Method and level set method were developed for efficient geometry optimization on sparse and dynamic data structures. Experimental results showed that the developed method is an order of magnitude faster than traditional algorithms, with minimal memory consumption.
COMPUTER-AIDED DESIGN
(2021)
Article
Multidisciplinary Sciences
Felipe A. S. Silva, Luis Junior, Jose Silva, Sandilya Kambampati, Leandro Salviano
Summary: Passive techniques such as longitudinal vortex generators have been studied for enhancing heat transfer in solar water heaters. Optimization of geometric parameters of LVG has shown significant improvement in heat transfer efficiency, with the highest augmentation of 62% at Reynolds number 900. Thermo-hydraulic efficiency is best at Reynolds number 600, with 55% heat transfer intensification.
SN APPLIED SCIENCES
(2021)
Article
Engineering, Multidisciplinary
Andreas Neofytou, Tsung-Hui Huang, Sandilya Kambampati, Renato Picelli, Jiun-Shyan Chen, H. Alicia Kim
Summary: This paper introduces a level set topology optimization method using the stabilized nodally integrated reproducing kernel particle method (RKPM) to solve governing equations, which provides an exact geometry description of a structure at each iteration without remeshing. The methodology demonstrates effectiveness, robustness, and ability to handle large topological changes, with the flexibility of using different particle distributions to increase efficiency. The useful characteristics of RKPM, such as easily controlled order of continuity and freely placing particles in a design domain, are illustrated through stress-based and design-dependent surface loading examples.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Thermodynamics
Sandilya Kambampati, Justin S. Gray, H. Alicia Kim
Summary: This study presents the optimal design of load carrying battery packs with heat exchange capabilities using a multi-objective optimization approach. The efficiency of the optimized designs is demonstrated through numerical examples by showcasing their multifunctional nature of reducing battery cell temperatures while sustaining a given load.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Mechanical
Quang Dat Tran, Sandilya Kambampati, H. Alicia Kim, Gang-Won Jang
Summary: A new three-dimensional structural optimization method based on the level set method is proposed to achieve uniform wall thickness in wire-fed metal additive manufacturing. The approach exploits the signed distance nature of a level set function to define the structure as a thin domain with uniform thickness, without the need for constraints or penalty functionals. Design velocity is represented by curvatures of the zero-level-set surface, and accurate computation of these curvatures is crucial for correct design sensitivities. The method achieves optimal accuracy by calculating mean and Gaussian curvatures through spatial averages over the Voronoi cell of each point on the discretized zero-level set.
JOURNAL OF MECHANICAL DESIGN
(2022)
Article
Computer Science, Interdisciplinary Applications
Sandilya Kambampati, Andrew Taber, Goldy Kumar, H. Alicia Kim
Summary: This paper presents a CAD-aware plug-and-play framework for topology optimization that produces CAD compatible-optimized geometries. The framework uses two separate kernels for geometry definition and updating, and for unfitted finite element analysis. The method efficiently produces lightweight designs optimized for minimum compliance and minimum stress, and allows for seamless export of optimized geometry as CAD compatible formats without the need for post-processing.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2023)