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A transversely injected jet into a hypersonic flow is simulated numerically in order to study the flow field of the injection jet in the hypersonic atmosphere, its heat flux on the body surface and the moments working on the body. The flowfields is governed by the two-dimentional Reynolds averaged full Navier-Stokes equations with an algebraic eddy viscosity model developed by Baldwin-Lomax. The governing equations are solved using the Harten-Yee type TVD and central difference schemes to the convex and viscous terms, respectively. The real gas effect is considered in the numerical analysis. The jets injected across the main flows of Mach 10 and 15 are compared.

In this paper, the numerical analysis of a three-point bending test of an aluminum foam sandwich structure is performed with the new extended finite element feature supported by Abaqus 6.9. The sandwich beam consists of two aluminum skins and one aluminum foam core. Three different sets of model dimensions are selected for comparison with the reference results (J. Yu, E. Wang, J. Li, Z. Zheng, “Static and low-velocity impact behavior of sandwich beams with closed-cell aluminum-foam core in three-point bending”, International Journal of Impact Engineering, 35, 2008, pp 885-894). Failure modes in this paper can be categorized into three parts: face yield (FY), indentation (IN), and core shear (CS). Face yield occurs on the surface of the core when the thickness of the skin is small. Indentation and core shear occur if the thickness of the skin is relatively large.

Three-dimensional solutions of the Navier-Stokes equations for a turbine blade with a turning angle of 180 degrees have been computed, including blade tip treatments involving cavities. The geometry approximates Pratt&Whitney's preliminary design for the GGOT (Generic Gas Oxidizer Turbine). The data presented here will be used as a means of comparison for experimental data to be obtained from a linear cascade being built and tested at The University of Alabama, using the original GGOT blades. Results have been computed for a blade with 1% clearance, based on chord, and three different cavity sizes. All tests were conducted at a Reynolds number of 4x107/m. The grid contains 39,440 points with 10 spanwise planes in the tip clearance region of 5.008E-04 m. Streamline plots and velocity vectors, together with velocity divergence plots reveal the general flow behavior in the clearance region.

The current paper presents the numerical study of the downwash flowfield characteristics in a cycloidal rotor at close-ground altitudes. In an aircraft equipped with this kind of thruster, the downwash flow plays significant role in different flight modes. The interaction of this downwash jet with ground in effective altitudes is studied using CFD simulations in OpenFOAM. Several operating conditions such as pitching oscillation angles, rotation speeds and height levels are all considered in this work. The results declare that close-ground operating states affects the performance of cyclorotors. The vertical and horizontal forces of a single blade is also analyzed in a complete cycloid in different operating conditions. A lead and lag in maximum and minimum extremes of force curves of a single blade is obtained while being subjected to different functional conditions.

A coupled analysis of inlet guide vanes, inducer blades, and the following struts is carried out via a Computational Fluid Dynamics (CFD) method. The complex 3-D components are part of a liquid hydrogen fuel turbopump for Advanced Expander Test Bed (AETB) engine. Numerical simulation is carried out via a 3-D compressible, Euler, finite volume, time-stepping algorithm that utilizes a multiple-grid accelerator for steady state problems. A scaling procedure is used to approximate the flow of liquids in turbopumps. Circumferential averaging at suitable planes in between the rotating and stationary components has been used to simulate the rotor/stator interactions in a steady state mode. The paper delineates the 3-D nature of the coupled flow fields through the pump components by simulating the conditions at normal operating point (20 K lb thrust) and an off-design point at 10 K lb thrust.

The existing two-dimensional Euler code is extended to the three-dimensional flow problem in which the transonic flow around the double fin-body combinations was analysed. Ni's two-dimensional formulas are extended to the three-dimensional case and applied to the supersonic flow calculation over the double fin-body combinations. The numerical results have proved to be very accurate in predicting the pressure distribution and capturing the shock. The code extended to the three-dimensional flow analysis in the paper can be consequently used to estimate the aerodynamic characteristics of the complicated body.

Numerical analysis by solving the three-dimensional Euler equations has been performed in order to investigate the complicated flow patterns or aerodynamic characteristics of the advanced turboprop (ATP) propeller with two types of spinner configuration. The governing equations are written for a rotating Cartesian coordinate system in terms of absolute flow variables. The solution algorithm used is an implicit approximate factorization method and resultant matrices are efficiently solved by LU-ADI scheme. Moreover, flux vectors are all treated implicitly in order to accelerate convergence. This solver has applied to study the effect of interference between highly swept blades and axisymmetrical spinner on aerodynamic performance of ATP propeller. Numerical results clearly captured overall structures of flow field such as shock formation and clarified that the selection of area-ruled spinner is important for aerodynamic design of an efficient turboprop.

The use of numerical control offers a method of reducing cost and assuring a more uniform product. Areas of economic consideration that are directly connected to numerical control include parts selection, machine load, second-source development, tooling, quantity, schedule, engineering product design, and program verification.

Preplanning, efficient programming, adequate maintenance technicians, and effective shop loading are the key areas in maintaining maximum utilization of numerically controlled machine tools. In order for management to know whether these groups are performing, a recording system which shows up time and down time is required. If a manual system is undesirable, there are several other types of monitors on the market.

A numerical analysis is conducted to investigate the performance degradation of iced airfoils in terms of meteorological parameters. Reference ice accretion shapes are taken from NASA's icing wind tunnel test results. Ice accretion shape and aerodynamic performance of the airfoil are numerically calculated under the same conditions as those used in the tests, and response surface equations are generated based on the results. The response surface models are applied to the conditions specified in Federal Aviation Regulations, appendix C of part 25, and the changes in aerodynamic coefficients are investigated. The areas of most significant lift and drag performance degradation overlap. The lift coefficient plunges more than 50% under temperatures greater than −10°C and LWC greater than 2g/m3. Under the same conditions, the drag performance greatly decreases as well. On the other hand, the moment coefficient greatly decreases under temperatures of less than −40°C and greater MVD.

The importance of the variation of relative humidity across turbomachinery engine components for in-flight icing is shown by numerical analysis. A species transport equation for vapor has been added to the existing CFD methodology for the simulation of ice growth and water flow on engine components that are subject to ice crystal icing. This entire system couples several partial differential equations that consider heat and mass transfer between droplets, crystals and air, adding the cooling of the air due to particle evaporation to the icing simulation, increasing the accuracy of the evaporative heat fluxes on wetted walls. Three validation cases are presented for the new methodology: the first one compares with the numerical results of droplets traveling inside an icing tunnel with an existing evaporation model proposed by the National Research Council of Canada (NRC).

Ice accretions on aircraft flight surfaces can degrade lift, increase drag, and reduce controllability. Anti-icing systems can remove or prevent ice growth. To predict the ice shrinkage or accretion using models such as LEWICE, the convective heat transfer behavior at the ice surface must be quantified. The work here is focused on understanding the convective heat transfer for several laser-scanned ice shapes by using commercial computational fluid dynamics (CFD) heat transfer simulations. The leading edge ice shape from a NACA 0012 airfoil and its geometrically unwrapped simplification are studied. Limitations encountered with a semi-automated unstructured mesh generation tool are presented. Thin boundary layer mesh thicknesses (i.e. much thinner than the flow’s viscous or thermal boundary layers) are found to be necessary in order to capture the surface curvature features and preserve good mesh quality near the geometric surface.

The study of aerodynamic forces in hypersonic environments is important to ensure the safety and proper functioning of aerospace vehicles. These forces vary with the angle of attack (AOA) and there exists an optimum angle of attack where the ratio of the lift to drag force is maximum. In this paper, computational analysis has been performed on a blunt cone model to study the aerodynamic characteristics when hypersonic flow is allowed to pass through the model. The flow has a Mach number of 8.44 and the angle of attack is varied from 0º to 20º. The commercial CFD solver ANSYS FLUENT is used for the computational analysis and the mesh is generated using the ICEM CFD module of ANSYS. Air is selected as the working fluid. The simulation is carried out for a time duration of 1.2 ms where it reaches a steady state and the lift and drag forces and coefficients are estimated. The pressure, temperature, and velocity contours at different angles of attack are also observed.

In this study we examined numerically the electrostatic spray transfer processes in the rotary bell spray applicator, which is this case implemented in a full 3D representation. Instead of an experimental approach [Stevenin et al., 2015, Fluids Eng., 137 (11)], here an algorithm implemented and developed for this simulation includes airflow, spray dynamics, tracking of paint droplets and an electrostatic modularized solver to present atomization and in-flight spray phenomena for the spray forming procedure. The algorithm is implemented using the OpenFOAM package. The shaping airflow is simulated via an unsteady 3D compressible Navier-Stokes method. Solver for particle trajectory was developed to illustrate the process of spray transport and also the interaction of airflow and particle that is solved by momentum coupling.

In a jet engine, ice accreted on a fan rotor can be shed from the blade surface due to centrifugal force, and the shed ice can damage compressor components. This phenomenon, which is referred to as ice shedding, threatens safe flight. However, there have been few studies on ice shedding because ice has numerous unknown physical parameters. Although existing icing models can simulate ice growth, these models do not have the capability to reproduce ice shedding. As such, in a previous study, we developed an icing model that takes into account both ice growth and ice shedding. In the present study, we apply the proposed icing model to a jet engine fan in order to investigate the effect of ice growth and shedding on the flow field. The computational targets of the present study are the engine fan and the fan exit guide vane (FEGV); thus, we simultaneously deal with the rotor-stator interaction problem.

This work presents the anti-icing simulation results from a pressure sensing probe. This study used various turbulence models to understand their influence in surface temperature prediction. A fully turbulence model and a transition turbulence model are considered in this work. Both dry air and icing conditions are considered for this study. The results show that at low Angle of Attack (AOA) both turbulence model results compared well and at higher AOA the results deviated. Overall, as AOA increases, the k-ꞷ SST model predicted the surface temperature colder than the Transition SST model result.

The purpose of this study is to investigate the effects of the size and location of wind fences on the rotor performance to avoid as well as quantify any adverse effects of outside wind on the measurement accuracy. To this end, firstly, a novel actuator disk method is developed which couples open source CFD code named OpenFOAM with blade element method and rotor flapping equations. Secondly, the parametric studies are conducted with respect to wind fence configurations which contain fence radius, inlet/outlet duct size and location etc. For quantitative evaluation of rotor performance variation according to inlet/outlet duct size, the mass flow and momentum rate on the ducts are. The rotor performance variation depending on the wind fence configuration is examined and consequently parametric study cases are classified according as calculated rotor thrust coefficient. Moreover, it is explained the difference of flow field in wind fence by demonstrating the pressure coefficient.

Streamwise vortices can be observed to interact in a number of real world scenarios. Vortex generators operating in boundary layers, as well as aircraft flying in formation can produce vortex interactions with multiple streamwise vortices in close proximity to each other. The tracking of these vortex paths as well as the location and nature of their breakdown is critical to determining how the structures can be used to aid flow control, and how large scale turbulence develops from them. Six configurations of two NACA0012 vanes were evaluated computationally to observe the interactions of a pre-existing vortex with a vortex generated downstream. Co and counter-rotating configurations at three different lateral spacings were used to vary vortex position and impingement on the rear vane.

A computational study of separated flows over a NACA 0012 airfoil at transitional Reynolds numbers is performed. The transitional nature of the flowfield is incorporated into the computations through γ-Reθ transition model based on local variables. Fully turbulent and transitional computations are performed for steady airfoil flowfields and computed results are compared against experiments. The γ-Reθ transition model, in association with Menter’s SST turbulence model is used for the transitional solutions while, SST turbulence model alone is used for the fully turbulent solutions. Both steady and unsteady compressible flow analysis for transition onset prediction and flow separation characterization has been performed. Effects of free stream flow conditions on flow transition are examined.

The aim of this paper is to present a numerical analysis of high-speed flows over a missile geometry. The N1G missile has been selected for our study, which is subjected to a high-speed flow at Mach 4 over a range of Angle of attack (AoA) from 0° to 6°. The analysis has been conducted for a 3-dimensional missile model using ANSYS environment. The study contemplates to provide new insights into the missile aerodynamic performance which includes the coefficient of lift (CL) , coefficient of drag (CD) and coefficient of moment (CM) using computational fluid dynamics (CFD). As there is a lack of availability of data for missile geometry, such as free stream conditions and/or the experimental data for a given Mach number, this paper intends to provide a detailed analysis at Mach 4. As the technology is advancing, there is a need for high-speed weapons (missiles) with a good aerodynamic performance, which intern will benefit in reduction of fuel consumption.