The paper is concerned with a node-based, gradient-driven, continuous adjoint two-phase flow procedure to optimize the shapes of free-floating vessels and discusses three topics. First, we aim to convey that elements of a Cahn–Hilliard formulation should augment the frequently employed Volume-of-Fluid two-phase flow model to maintain dual consistency. It is seen that such consistency serves as the basis for a robust primal/adjoint coupling in practical applications at huge Reynolds and Froude numbers. The second topic covers different adjoint coupling strategies. A central aspect of the application is the floating position, particularly the trim and the sinkage, that interact with a variation of hydrodynamic loads induced by the shape updates. Other topics addressed refer to the required level of density coupling and a more straightforward—yet non-frozen—adjoint treatment of turbulence. The third part discusses the computation of a descent direction within a node-based environment. We will illustrate means to deform both the volume mesh and the hull shape simultaneously and at the same time obey technical constraints on the vessel’s displacement and its extensions. The Hilbert-space approach provides smooth shape updates using the established coding infrastructure of a computational fluid dynamics algorithm and provides access to managing additional technical constraints. Verification and validation follow from a submerged 2D cylinder case. The application includes a full-scale offshore supply vessel at $$\mathrm{Re} = 3 \times 10^8$$ Re = 3 × 10 8 and $$\mathrm{Fn} = 0.37$$ Fn = 0.37 . Results illustrate that the fully parallel procedure can automatically reduce the drag of an already pre-optimized shape by 9–13% within $$\approx\,{\mathcal{O}}$$ ≈ O (10,000-30,000) CPUh depending on the considered couplings and floatation aspects.
The revived popularity of vinyl records in the United States provides a unique opportunity for ‘rethinking the distinction between new and old media’. With vinyl, the new/old dichotomy informs a more specific opposition between digital and analog. The vinyl record is an iconic analog artifact whose physical creation and circulation cannot be digitized. Making records involves arduous craft labor and old-school manufacturing, and the process remains essentially the same as it was in 1960. Vinyl culture and commerce today, however, abound with digital media: the majority of vinyl sales occur online, the download code is a familiar feature of new vinyl releases, and turntables outfitted with USB ports and Bluetooth are outselling traditional models. This digital disconnect between the contemporary traffic in records and their fabrication makes the vinyl revival an ideal case example for interrogating the limitations of new and old as conceptual horizons for media and for proffering alternative historical formulations and critical frameworks. Toward that end, my analysis of the revitalized vinyl economy in the United States suggests that the familiar (and always porous) distinction between corporate and independent continues to offer media studies a more salient spectrum, conceptually and empirically, than new-old or analog-digital. Drawing on ethnographic research along vinyl’s current supply chain in the United States, I argue that scholars and supporters of independent culture should strive to decouple the digital and the analog from the corporate, rather than from one another. The pressing question about the future of vinyl is not, will there continue to be a place for analog formats alongside the digital; but rather, to what extent can physical media circulate independently of the same corporate interests that have come to dominate popular culture in its digital forms?
After sustained growth for over a decade among independent record labels and retail outlets, major labels and chain stores embraced vinyl records as a growth sector, and for the first time in half a century, demand began outpacing supply. In this essay, I analyze recent trends of vinyl traffic and critique a prominent feature of contemporary vinyl culture: Record Store Day. The annual holiday has boosted vinyl sales while become an inflationary engine driving up costs, which alongside sales have skyrocketed since the turn of the century. At stake is a sustainable supply chain for recorded popular music that is not beholden to online access to digitized content and that can thrive outside the grip of corporate retail machinery. I describe how pressing plants and independent labels are coping with the surge in demand for vinyl records, and to conclude I suggest how supporters and scholars of independent music can more effectively combat corporate control by decoupling it from digitization as two distinct phenomena. For lovers as well as makers of independent music, the major labels' reembrace of an analog format like vinyl can be as threatening as the corporate stranglehold on digital distribution.
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