On the role and challenges of CFD in the aerospace industry

Abstract

This article examines the increasingly crucial role played by Computational Fluid Dynamics (CFD) in the analysis, design, certification, and support of aerospace products. The status of CFD is described, and we identify opportunities for CFD to have a more substantial impact. The challenges facing CFD are also discussed, primarily in terms of numerical solution, computing power, and physical modelling. We believe the community must find a balance between enthusiasm and rigor. Besides becoming faster and more affordable by exploiting higher computing power, CFD needs to become more reliable, more reproducible across users, and better understood and integrated with other disciplines and engineering processes. Uncertainty quantification is universally considered as a major goal, but will be slow to take hold. The prospects are good for steady problems with Reynolds-Averaged NavierStokes (RANS) turbulence modelling to be solved accurately and without user intervention within a decade -even for very complex geometries, provided technologies, such as solution adaptation are matured for large three-dimensional problems. On the other hand, current projections for supercomputers show a future rate of growth only half of the rate enjoyed from the 1990s to 2013; true exaflop performance is not close. This will delay pure LargeEddy Simulation (LES) for aerospace applications with their high Reynolds numbers, but hybrid RANS-LES approaches have great potential. Our expectations for a breakthrough in turbulence, whether within traditional modelling or LES, are low and as a result offdesign flow physics including separation will continue to pose a substantial challenge, as will laminar-turbulent transition. We also advocate for much improved user interfaces, providing instant access to rich numerical and physical information as well as warnings over solution quality, and thus naturally training the user. This is an invited paper to mark the 150 th anniversary of the founding of the Royal Aeronautical Society in January 1866.

Computational Modelling of Wing Downwash Profile with Reynolds-Averaged and Delayed Detached-Eddy Simulations

“…These demanding requirements have been highlighted 19,21 and the DDES case here utilizes 90 million elements with just the refinement box capturing part of the downwash. At these spatial and temporal scales, approximately 9 days of computational time and 1 TB of data are used just for the transient case.…”

“…Then, a more advanced model, DES (Detached Eddy Simulations) that employs a hybrid RANS/LES (Large Eddy Simulations) modelling technique is used. 21 Conceptually, DES treats the near-wall with RANS formulations whereas regions farther are treated with LES. This reduces computational, but not necessarily grid 22 requirements, especially near the walls but simultaneously allows LES-like modelling for regions further from the walls.…”

Development and verification of CFD model of carbothermal synthesis furnace for production of mixed nitride uranium-plutonium fuel

“…For the past three decades, there has been an increasing tendency to use the Computational Fluid Dynamics (CFD) methods for computational justifications of engineering solutions in designing various industrial facilities (Spalart and Venkatakrishnan 2016, Raynal et al 2016, Mizzi et al 2015, Joshi and Nayak 2019. Using modern CFD codes enables modeling heat and mass transport, hydro-and gas dynamics hard to reproduce experimentally.…”

Coupling of an Unsteady Aerodynamics Model with a Computational Fluid Dynamics Solver

“…Fully-resolved Navier-Stokes simulations of wings and rotor blades have been established as a means of predicting aerodynamics in both steady and unsteady conditions for most regions of the operational envelope [1,2]. Provided the expertise, appropriate validation, and the computational resources these simulations can produce accurate predictions of performance, though challenges remain for analysis of complex configurations [3] and prediction of sensitive parameters such as rotor figure of merit [4].…”