Naval Surface Warfare Center

About: Naval Surface Warfare Center is a facility organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Sonar & Radar. The organization has 2855 authors who have published 3697 publications receiving 83518 citations. The organization is also known as: NSWC.

Application of a panel method to hydrodynamics of underwater vehicles

Abstract: A low-order singularity panel method based on Green`s formulation is used to predict the hydrodynamics characteristics of underwater vehicles. The low-order modeling employs constant strength sources and doublets, and the body surface is modeled by quadrilaterals. The method is first applied to predicting the force and moment coefficients of underwater vehicles for the body-alone and finned configurations. Hydrodynamic coefficients of added mass and added moment of inertia are also calculated by modifying the code. Results for several two and three-dimensional bodies show the usefulness of the method for predicting the added mass and added moment of inertia.

A compressible two-phase model for dispersed particle flows with application from dense to dilute regimes

Abstract: Multiphase flows are present in many important fields ranging from multiphase explosions to chemical processing. An important subset of multiphase flow applications involves dispersed materials, such as particles, droplets, and bubbles. This work presents an Eulerian–Eulerian model for multiphase flows containing dispersed particles surrounded by a continuous media such as air or water. Following a large body of multiphase literature, the driving force for particle acceleration is modeled as a direct function of both the continuous-phase pressure gradient and the gradient of intergranular stress existing within the particle phase. While the application of these two components of driving force is well accepted in much of the literature, other models exist in which the particle-phase pressure gradient itself drives particle motion. The multiphase model treats all phases as compressible and is derived to ensure adherence to the 2nd Law of Thermodynamics. The governing equations are presented and discussed, and a characteristic analysis shows the model to be hyperbolic, with a degeneracy in the case that the intergranular stress, which is modeled as a configuration pressure, is zero. Finally, results from a two sample problems involving shock-induced particle dispersion are presented. The results agree well with experimental measurements, providing initial confidence in the proposed model.

Large Eddy Simulation of a Circulation Control Airfoil

Abstract: A detailed study of the compressible, turbulent flow around a circulation control airfoil has been conducted using a large eddy simulation (LES). The circulation control airfoil investigated is the NCCR 1510-7067N, which has a circular arc shaped trailing edge. The Reynolds number for the problem is 5.45x10, based on chord, with a free stream Mach number of 0.12. The non-dimensional blowing rate (Cμ) for the Coanda jet is 0.093. The filtered Navier-Stokes equations are discretized using a fifth-order spatially accurate, upwind scheme with no limiting. The sub-grid scale turbulence model combines a transport equation for the sub-grid scale turbulent kinetic energy with a turbulent length scale, based on local grid dimensions, to form a expression for the sub-grid scale eddy viscosity. The resulting mean surface pressure distribution compares fairly well to experimentally measured values for the airfoil. Resulting mean velocity and Reynolds stress profiles at selected locations around the airfoil are examined.

Instructor strategies to aid implementation of active learning: a systematic literature review

Abstract: Despite the evidence supporting the effectiveness of active learning in undergraduate STEM courses, the adoption of active learning has been slow. One barrier to adoption is instructors’ concerns about students’ affective and behavioral responses to active learning, especially student resistance. Numerous education researchers have documented their use of active learning in STEM classrooms. However, there is no research yet that systematically analyzes these studies for strategies to aid implementation of active learning and address students’ affective and behavioral responses. In this paper, we conduct a systematic literature review and identify 29 journal articles and conference papers that researched active learning, affective and behavioral student responses, and recommended at least one strategy for implementing active learning. In this paper, we ask: (1) What are the characteristics of studies that examine affective and behavioral outcomes of active learning and provide instructor strategies? (2) What instructor strategies to aid implementation of active learning do the authors of these studies provide? In our review, we noted that most active learning activities involved in-class problem solving within a traditional lecture-based course (N = 21). We found mostly positive affective and behavioral outcomes for students’ self-reports of learning, participation in the activities, and course satisfaction (N = 23). From our analysis of the 29 studies, we identified eight strategies to aid implementation of active learning based on three categories. Explanation strategies included providing students with clarifications and reasons for using active learning. Facilitation strategies entailed working with students and ensuring that the activity functions as intended. Planning strategies involved working outside of the class to improve the active learning experience. To increase the adoption of active learning and address students’ responses to active learning, this study provides strategies to support instructors. The eight strategies are listed with evidence from numerous studies within our review on affective and behavioral responses to active learning. Future work should examine instructor strategies and their connection with other affective outcomes, such as identity, interests, and emotions.