Italian Aerospace Research Centre

About: Italian Aerospace Research Centre is a other organization based out in Capua, Campania, Italy. It is known for research contribution in the topics: Aerodynamics & Morphing. The organization has 278 authors who have published 400 publications receiving 3563 citations. The organization is also known as: CIRA & Italian Aerospace Research Center.

Value-at-Risk and Conditional Value-at-Risk in Optimization Under Uncertainty

Abstract: This work is related to the use of various risk measures in the context of robust- and reliability-based optimization. We start from the definition of risk measure and its formal setting, and then, we show how different risk functional definitions can lead to different approaches to the problem of optimization under uncertainty. In particular, the application of value-at-risk (VaR) and conditional value-at-risk (CVaR), also called quantiles and superquantiles, is here illustrated. These risk measures originated in the area of financial engineering, but they are very well and naturally suited to reliability-based design optimization problems and they represent a possible alternative to more traditional robust design approaches. We will then discuss the implementation of an efficient risk measure-based optimization algorithm based on the introduction of the weighted empirical cumulative distribution function (WECDF) and on the use of methods for changing the probability measure. Subsequently, we will discuss the problems related to the error in the estimation of the risk function and we will illustrate the “bootstrap” computational statistics technique to get an estimate of the standard error on VaR and CVaR. Finally, we will report some simple application examples of this approach to robust and reliability-based optimization.

Model for Enhancing Turbulent Production in Laminar Separation Bubbles

Abstract: Laminar separation bubbles are one of the main critical aspects of flows at low Reynolds numbers in the range of 104–105. The flow separates in the laminar regime, the turbulence developing inside ...

Aerothermodynamics and thermal design for on-ground and in-flight testing of a deployable heat shield capsule

Abstract: The article deals with the aerothermodynamic and thermal analysis of two technological demonstrators suitable for research activities on deployable heatshield entry capsules. Variable geometry bodies represent a formidable way to build low ballistic coefficient entry platforms able to limit convective heat fluxes, mechanical loads, and final descent velocity. These characteristics suggest several interesting applications for space missions such as to exploit those systems for human or large payloads landing on Mars. The main feature of the demonstrators is the umbrella-like deployable heatshield made of a flexible thermal protection system. In this framework, the work reports on the design analyses carried out for a flight and a ground demonstrator developed to prove, with suborbital flight and plasma wind tunnel test campaigns, several key technologies of the deployable heatshield. Several non-equilibrium three-dimensional flowfield simulations were performed to assess the aerothermal loading conditions expected for the demonstrators. Pressure and heat flux distributions on the deployable heatshield are provided and discussed. Finally, those surface loading conditions are set to feed a finite-element thermal analysis of the demonstrators, also detailed in the work.