A nonlinear mathematical model with a free moving boundary was introduced to study viscous flow in stenotic elastic tubes subject to a prescribed external pressure at the tube wall and pulsatile pressure drop between the tube inlet and outlet. An iterative numerical method using boundary iteration, pseudocompressibility, and the ADI technique was developed to solve the model. Unsteady effects o...

This paper presents an adjoint method for the optimal control of unsteady flows. The goal is to develop the continuous and discrete unsteady adjoint equations and their corresponding boundary conditions for the time accurate method. First, this paper presents the complete formulation of the time dependent optimal design problem. Second, we present the time accurate unsteady continuous and discr...

In real systems, the phenomena, such as pipe-wall viscoelasticity, unsteady friction or fluid structure interaction induce additional damping and dispersion of transient pressure waves than that defined by classical waterhammer. In this paper, unsteady friction models and viscoelastic damping models will be presented and a theoretical formulation of the viscoelastic damping in piping systems wi...

The results from two numerical simulations of the unsteady flow in a 1-1/2 stage axial-flow turbine are presented and compared with experimental data to show both the effect of blade count on the solution accuracy and the time-averaged and unsteady flow physics present. The TFLO three-dimensional, multi-block, massively parallel turbomachinery flow solution procedure is used to simulate the flo...

In this paper, the results of flow-control experiments using single dielectric barrier discharge plasma actuators to controlflow separation andunsteady vortex shedding froma circular cylinder in crossfloware reported. Thiswork is motivated by the need to reduce landing gear noise for commercial transport aircraft via an effective streamlining created by the actuators. The experiments are perfor...

sonic Unsteady Lifting Surfaces," AIAA Journal, Vol. 22, No. 2, 1984, pp. 179-186. Tewari, A., "Nonplanar Doublet-Point Method in Supersonic Three-Dimensional, Unsteady Aerodynamics," M.S. Thesis, Univ. of Missouri-Rolla, Rolla, MO, 1988. Tewari, A., "New Acceleration Potential Method for Supersonic Unsteady Aerodynamics of Lifting Surfaces, Further Extension of the Nonplanar Doublet Point Meth...

Flow volumes [1] are extended for use in unsteady (timedependent) flows. The resulting unsteady flow volumes are the 3 dimensional analog of streaklines. There are few examples where methods other than particle tracing have been used to visualize time varying flows. Since particle paths can become convoluted in time there are additional considerations to be made when extending any visualization...

This paper presents a time-accurate procedure for computing unsteady aerodynamic forces on wings with a full-span oscillating control surface by using sheared grids. In this procedure, the flow is computed by solving the unsteady Reynolds-Averaged Navier-Stokes (RANS) equations in conjunction with the one-equation Spalart-Allmaras turbulence model. A module to model control surface oscillations...

Recent enhancements to the development of CFD-based unsteady aerodynamic and aeroelastic reduced-order models (ROMs) are presented. These enhancements include the simultaneous application of structural modes as CFD input, static aeroelastic analysis using a ROM, and matched-point solutions using a ROM. The simultaneous application of structural modes as CFD input enables the computation of the ...

in petroleum production, produced water re-injection (pwri) has earned much interest among disposal methods of the produced water. however, presence of the contaminants in the produced waters usually results in formation damage in well bores and their surrounding fracture systems. in the present study, modeling of external cake formation on a fracture in unsteady-state conditions is discussed. ...