This paper presents the development and application of a time-dependent adjoint-based method for aeroacoustic design optimization of flexible helicopter rotors in forward flight. The rotor noise signature at a farfield observer is computed with the hybrid aeroacoustic approach in which a near-body coupled computational fluid dynamics/computational structural dynamics solver provides flow and geometry data to an FW-H acoustic module that propagates the acoustic waves to a farfield observer. Forward and adjoint sensitivity formulations are derived that correspond to analogues of the multidisciplinary flexible aeroacoustic analysis problem. The newly implemented aeroacoustic capability is first verified to effectively perform forward flight noise prediction by comparison with the PSU-WOPWOP acoustic tool. Upon successful validation, a gradient based optimization method is used to minimize the required torque of the flexible HART-II rotor in trimmed forward flight while reducing the acoustic signature at a farfield observer by changing the shape of the blades. The adjoint formulation developed in this work is used to efficiently compute the sensitivity required by the optimization algorithm.
The OpenDBDDAS Toolkit is a software framework to provide support for more easily creating and expanding dynamic big data-driven application systems (DBDDAS) that are common in environmental systems, many engineering applications, disaster management, traffic management, and manufacturing. In this paper, we describe key features needed to implement a secure MapReduce and Hadoop-like system for high performance clusters that guarantees a certain level of privacy of data from other concurrent users of the system. We also provide examples of a secure MapReduce prototype and compare it to another high performance MapReduce, MR-MPI.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.