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In surgery, tissue and organ bleeding is common and unavoidable. Adding bleeding simulation to virtual surgery can greatly improve the visual realism of the surgical environment, and can also train surgeons' reactions to surgical bleeding. Blood is a kind of viscous and incompressible liquid, and has unique mechanical properties due to the existence of platelets and other cells. The Navier-Stokes...
Accurate mathematical models especially accurate hydrodynamic parameters of unmanned underwater vehicles (UUVs) are essential for good control performance. This paper provides a general framework for the hydrodynamic modeling of a small-scale UUV. In place of physical experiments such as captive model tests, a virtual model test and simulation was conducted via commercial computational fluid dynamics...
Remote Operated Vehicles(ROV) play an important role in marine economic development, environmental protection and disaster management. This paper introduces the design procedure for the rudder wing of ROV used in marine shallow water areas. First of all, the wing selection of the rudder wing is chosen based on the maneuverability requirements of the ROV Secondly, the 3D model of the rudder wing is...
Autonomous underwater vehicles (AUV) are attractive platforms for many applications in the off-shore industry. The design and development of an AUV is an expensive and complex task. During the development of these vehicles both at the stage of physical design for construction, as in the stage of the navigation system design, it is critical to estimate and analyze the dynamic behavior of these vehicles...
Sediment transport at the Yellow river delta is affected by many different factors, including tide, waves and river flows. With the change of river exit in 1996, a new delta is rapidly growing which leads to a new sediment transport regime. Most existing computer modelling work at the site is yet to take such changes into account. In addition, the wave action at the river mouth is often ignored in...
Long-term hemodialysis is frequently provided with an arteriovenous (AV) graft implanted into an extremity. The useful life of AV grafts is limited by the development of stenosis at or downstream from the venous anastomosis. A better understanding of graft hemodynamics may allow improved assessment of the risk of thrombosis. Jones et al (J Biomech Eng 2005, 127: 60-66) developed a model of pressure...
The physical process modeling of an estuary is a complex mechanism that comes along with the existence of uncertainty. In contrast, due to significant variability of flows in space and time, an extensive modeling effort must be accommodated with the application of parallelization technology. Therefore, the implication of estuary model parallelization to the model result uncertainty must be examined...
National Research Council Canada (NRC) is collaborating with College of the North Atlantic (CNA) to develop an ocean wave-driven pump to supply the CNA shore-based aquaculture centre in Lord's Cove, Newfoundland. NRC provides a combination of physical model testing under controlled laboratory conditions and computer simulation using numerical modelling tools developed at NRC and commercial software...
Two-DOF barycenter mechanism and its control are proposed. The mechanism by means of the moved balancing masses along two axes changes the center of gravity of fish's body. The projected torques on x and y axes propel pitch and roll angles to the desired values. Merging the pitching and rolling models with fish-tail and rigid-body models, the fish robot motion and maneuverability can be achieved in...
Wave energy converter research continues to advance and new developers are continuing to emerge, leading to the need for a general modeling methodology. This work attempts to outline the design methodology necessary to perform frequency domain analysis on a generic wave energy converter. A two-body point absorber representing a generic popular design was chosen and a general procedure is presented...
This paper describes numerical methods for a four-moments quantum energy transport(QET) model, which is derived by using a diffusion scaling in the quantum hydrodynamic model. Space discretization is performed by a new set of unknown variables. Numerical stability and convergence are obtained by developing an iterative solution method with a relaxation method. Numerical results in a scaled MOSFET...
Transport equations of gas-solid flows are filtered by means of the volume fraction weighted average method. The filtered equations for gas phase and solid phase are derived, and Euler-Euler two-fluid large eddy simulation model of dense gas-solid flows is presented. The model is used to simulate the hydrodynamics of gas-solid two-phase flows in a riser. The model predicts the core-annular structure...
According to the characteristic of unmanned surface vehicle(USV) based on water-jet propulsion, four-degree of freedom maneuvering motion equation was established. External forces acting on USV were divided into gravity, buoyancy, inertial hydrodynamic force, viscous hydrodynamic force, dynamic lift force and water-jet force. Besides MFC frame, Creator and Vega were adopted. Maneuvering simulation...
We present a new particle-based method for high viscosity fluid simulation. In the method, a new elastic stress term, which is derived from a modified form of the Hooke's law, is included in the traditional Navier-Stokes equation to simulate the movements of the high viscosity fluids. Benefiting from the Lagrangian nature of Smoothed Particle Hydrodynamics method, large flow deformation can be well...
The hydrodynamics of a two-dimensional bed reactor were studied computationally. To describe the particulate phase stress in the Eulerian-Eulerian two-fluid model, the kinetic theory of granular flow has been used. Syamal O'Brien drag function was used to calculate momentum exchange coefficients between gas and solid phases. We specified diameter of glass beads which is 300μm and restitution coefficient...
A fully calibrated three-dimensional hydrodynamic model, namely Curvilinear Hydrodynamics in 3-Dimensions (CH3D), has been developed to determine changes of flow velocity in a natural river. The objective of this paper is to present the application of the CH3D modeling. A grid scheme was constructed by using SMS software along an example river-the Detroit River from Lake St. Clair to Lake Erie with...
A two-dimensional dam-break flood simulation model using unstructured meshes has been developed to study the hydrodynamics of flooding processes. The model employs the finite volume method to solve the conservation form of the shallow water equations. The HLLC approximate Riemann solver is used for computing the fluxes at cell interfaces because of its easiness to implement and suitability to wet/dry...
Based on turbulent model, this paper has established a 3D flow and sediment mathematical model under orthogonal curvilinear system, numerically simulating the free water surface, the flow velocity structure, the sediment content distribution of a 180°sharp curved open channel, as well as the bed deformation effected by complicated flow field of curved channel. Validation and analysis have been made...
An accurate and highly efficient semi-implicit three-dimensional tidal model is developed and has been applied to real area. In the model, the pressure gradient in the momentum equations and the velocities in the vertically integrated continuity equations are discretized using the θ-method, the vertical mixing terms are discretized implicitly and all the other terms are discretized explicitly. The...
This paper is concerned with a mathematical model for simulating hydrodynamics of 2D river flow with groins based on the WENO scheme and the Finite Volume Method on unstructured grids. The time discretization uses the Runge-Kutta TVD scheme. By using the proposed model, we calculated the flow property with a groin, and obtained the flow velocity field distributions. The comparisons of the calculated...
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