Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 11 of 11 for “"DDES"”.
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Stability Analysis of Time Delay Systems Using Spectral Element Method
… of various delay differential equations (DDEs). The development of these new analysis techniques is motivated by the existence of delays in the governing equations of many physical systems such as turning and milling processes. </p><p>Delay differential equations appear in many models in …
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Galerkin Approximations of General Delay Differential Equations with Multiple Discrete or Distributed Delays
Delay differential equations (DDEs) are often used to model systems with time-delayed effects, and they have found applications in fields such as climate dynamics, biosciences, engineering, and control theory. In contrast to ordinary differential equations (ODEs), the phase space associated even …
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MODELING THE DYNAMICS OF INFECTIOUS DISEASES WITH Latency IN SPATIALLY HETEROGENEOUS Environments
… by a system of delay differential equations (DDEs). It is a generalization of the classical Kermack-McKendrick SIR model, and it preserves some properties that the Kermack-McKendrick model processes. We show that the ratio of final sizes in two patches is fully determined by the ratio of …
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A Preliminary Study of Acoustic Prediction Technology Based on Detached Eddy Simulations for Supersonic Jets Impinging on Flat Plates
… known as Delayed Detached Eddy Simulation (DDES). A transient solution is calculated using the pressure-based coupled solver formulation with the second-order bounded central-upwind spatial discretization and second-order implicit time marching scheme. Flow features like the stagnation …
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Propeller Noise Prediction of an Urban Air Mobility Vehicle in Urban Environment
… (DES) and Delayed Detached Eddy Simulation (DDES)—are coupled with the Ffowcs–Williams and Hawkings (FW–H) acoustic analogy to capture both unsteady flow dynamics and far-field sound radiation.</p> <p>The first part focuses on the investigation to transition (tilt) flight conditions, where …
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Stability analysis of a natural circulation lead-cooled fast reactor
… by sets of ODEs with time lags, namely, DDEs, due to external pipes and the HX model. Models 1 and 2 use a constant heat source term rather than coupled neutronics as is the case in model 3. In model 3, the four equivalent loops are linked via modal neutronics. They are represented by …
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High-Fidelity Modeling of eVTOL Rotor Unsteady Aerodynamic and Aeroacoustic Response to Time-Harmonic Gust
… Delayed Detached Eddy Simulation (SA-DDES) turbulence model. Second, a time-harmonic gust generator is implemented via a localized momentum-source formulation to create convected inflow disturbances with controlled amplitude and frequency, verified to maintain phase and amplitude …
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Business Cycle Models with Embodied Technological Change and Poisson Shocks
… which is based on a modified method of steps for DDEs. It provides not only approximations but also upper and lower bounds for optimal consumption path and steady state. Furthermore, analytical expressions for the long-term equilibrium distributions of the stationary variables of the model are …
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Eddy-resolving simulations of the flow around a vertical tail plane
… the form of Delayed Detached-Eddy Simulations (DDES) are used to assess the characteristics of the separated flow around the tail plane. Results show a remarkable improvement of the flow solution. The pressure distribution matches experimental results favourably, and this translates into an …
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IT’S MORE THAN A RAMP! The Comprehensive Accessibility Enhancement Package (CAEP) for Public Spaces
Urban environments quite often do not meet accessibility requirements. This thesis examines how Cities can make their built environments accessible, inclusive and welcoming. Using a design and research science approach this thesis developed a response in the form of the Comprehensive Accessibility …
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Impact Fiction: the Gentle Art of Bending the Near Future.
This dissertation presents, and performs, a novel way of practicing design, to inform the core methodology of a new design practice; one seeking near future impact-innovation outcomes — cornerstoned to build Agency for our Elder* segment. The mainstay thesis question, evolved to ask: ‘How can …