Effect of rocket exhaust of canisterized missile on adjoining launching system

2016 ◽  
Vol 231 (11) ◽  
pp. 2085-2097 ◽  
Author(s):  
MSR Chandra Murty ◽  
PK Sinha ◽  
D Chakraborty
Keyword(s):  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Test Configuration ◽  
Instantaneous Position ◽  
Flow Features ◽  
Scale Down ◽  
Parametric Studies

Transient numerical simulations are carried out to study missile motion in a vertical launch system and to estimate the effect of missile exhaust in the adjoining launch structure. Three-dimensional Navier–Stokes equations along with k–ɛ turbulence model and species transport equations are solved using commercial computational fluid dynamics software. Dynamic grid movement is adopted and one degree of freedom trajectory equations are integrated with the computational fluid dynamic solver to obtain the instantaneous position of the missile. Multi-zone grid generation approach with sliding interface method through layering technique is adopted to address the changing boundary problem. The computational methodology is applied to study the missile motion in a scale-down test configuration as well as in the flight condition. The computations capture all essential flow features of test and flight conditions in active cell as well as in adjacent cells. Parametric studies are conducted to study the effect geometrical features and measurement uncertainty in the input data. Computed pressures in the adjacent cells in the launch system match better (∼12%) with the experimental and flight results compared to distant cells.

The inlet flow structure of a conceptual open-nose supersonic drone

2021 ◽  
pp. 095441002098304
Author(s):  
Eiman B Saheby ◽  
Xing Shen ◽  
Anthony P Hays ◽  
Zhang Jun
Keyword(s):  
Flow Structure ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Computational Fluid Dynamic Simulation ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Navier Stokes Equations ◽  
Aerodynamic Efficiency ◽  
Performance Effects

This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

scholarly journals Numerical and Analytical Study of Fluid Dynamic Forces in Seals and Bearings

1988 ◽  
Vol 110 (3) ◽  
pp. 315-325 ◽  
Author(s):  
L. T. Tam ◽  
A. J. Przekwas ◽  
A. Muszynska ◽  
R. C. Hendricks ◽  
M. J. Braun ◽  
...  
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Circumferential Velocity ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Lumped Model ◽  
Destabilizing Factors ◽  
Recirculation Zones

A numerical model based on a transformed, conservative form of the three-dimensional Navier-Stokes equations and an analytical model based on “lumped” fluid parameters are presented and compared with studies of modeled rotor/bearing/seal systems. The rotor destabilizing factors are related to the rotative character of the flow field. It is shown that these destabilizing factors can be reduced through a descrease in the fluid average circumferential velocity. However, the rotative character of the flow field is a complex three-dimensional system with bifurcated secondary flow patterns that significantly alter the fluid circumferential velocity. By transforming the Navier-Stokes equations to those for a rotating observer and using the numerical code PHOENICS-84 with a nonorthogonal body fitted grid, several numerical experiments were carried out to demonstrate the character of this complex flow field. In general, fluid injection and/or preswirl of the flow field opposing the shaft rotation significantly intensified these secondary recirculation zones and thus reduced the average circumferential velocity, while injection or preswirl in the direction of rotation significantly weakened these zones. A decrease in average circumferential velocity was related to an increase in the strength of the recirculation zones and thereby promoted stability. The influence of the axial flow was analyzed. The lumped model of fluid dynamic force based on the average circumferential velocity ratio (as opposed to the bearing/seal coefficient model) well described the obtained results for relatively large but limited ranges of parameters. This lumped model is extremely useful in rotor/bearing/seal system dynamic analysis and should be widely recommended. Fluid dynamic forces and leakage rates were calculated and compared with seal data where the working fluid was bromotrifluoromethane (CBrF3). The radial and tangential force predictions were in reasonable agreement with selected experimental data. Nonsynchronous perturbation provided meaningful information for system lumped parameter identification from numerical experiment data.

scholarly journals RUBBLE MOUND BREAKWATER OVERTOPPING: ESTIMATION OF THE RELIABILITY OF A 3D NUMERICAL SIMULATION

2012 ◽  
Vol 1 (33) ◽  
pp. 8 ◽  
Author(s):  
Luca Cavallaro ◽  
Fabio Dentale ◽  
Giovanna Donnarumma ◽  
Enrico Foti ◽  
Rosaria E. Musumeci ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Complex Geometry ◽  
Fluid Dynamic ◽  
Complete Solution ◽  
Three Dimensional ◽  
Design Tool ◽  
Physical Models ◽  
Navier Stokes ◽  
Free Boundaries ◽  
Navier Stokes Equations

Until recently, physical models were the only way to investigate into the details of breakwaters behavior under wave attack. From the numerical point of view, the complexity of the fluid dynamic processes involved has so far hindered the direct application of Navier-Stokes equations within the armour blocks, due to the complex geometry and the presence of strongly non stationary flows, free boundaries and turbulence. In the present work the most recent CFD technology is used to provide a new and more reliable approach to the design analysis of breakwaters, especially in connection with run-up and overtopping. The solid structure is simulated within the numerical domain by overlapping individual virtual elements to form the empty spaces delimited by the blocks. Thus, by defining a fine computational grid, an adequate number of nodes is located within the interstices and a complete solution of the full hydrodynamic equations is carried out. In the work presented here the numerical simulations are carried out by integrating the three-dimensional Reynolds Average Navier-Stokes Equations coupled with the RNG turbulence model and a Volume of Fluid Method used to handle the dynamics of the free surface. The aim of the present work is to investigate the reliability of this approach as a design tool. Two different breakwaters are considered, both located in Southern Sicily: one a typical quarry stone breakwater, another a more complex design incorporating a spill basin and an armoured layer made up by Coreloc® blocks.

scholarly journals A novel parallel algorithm for 3D modelling electromagnetic purification of water

2018 ◽  
Vol 210 ◽  
pp. 04027
Author(s):  
Tatiana Kudryashova’ ◽  
Sergey Polyakov ◽  
Nikita Tarasov
Keyword(s):  
Mathematical Modelling ◽  
Field Experiments ◽  
Stokes Equations ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Physical Structure ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Purification System ◽  
Modelling Problem

The computational fluid dynamic research in this work has focused on the problem of full-scale three-dimensional modelling water purification processes by the electromagnetic method. Presently, this method of purification was used in the final stage of processing for the production of ultrapure water. In spite of many field experiments, detailed data on such processes can be obtained only by the mathematical modelling. This way allows us to take into account many aspects, for example: real three-dimensional geometry, physical structure of the purification system, heterogeneous composition of the impurities, etc. And also, the mathematical modelling helps to optimize many parameters in order to improve a design of the purification system. Within the framework of the modelling problem, one of the important aspects is the correct description of the three-dimensional flow inside a specific purification system. For this purpose, various mathematical models and numerical approaches are implemented. In this paper, the flow calculation was realized on basis of the Navier-Stokes equations.

scholarly journals The Modelling of Flow in the Volute and Vanes of a High Pressure Radial Inflow Turbine

1993 ◽  
Author(s):  
M. Lobo ◽  
R. L. Elder
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Experimental Measurements ◽  
General Description ◽  
Navier Stokes Equations ◽  
Flow Modelling ◽  
Comparison With Experiment ◽  
Flow Features ◽  
Radial Inflow Turbine

The flow in a vaned volute of a radial inflow turbine is analysed using PHOENICS, a very general three-dimensional viscous CFD code based on finite-volume pressure-correction techniques for solving the Navier-Stokes equations. The study involves two physically complementary but mathematically very different problems — flow modelling in the vaneless section of the volute and flow modelling in the vanes. Each of these problems is considered in turn — and each presents characteristic hurdles. Particular attention is paid to grid-generation and the process is carried out alongside the flow computation, the grids being modified in such a way so as to facilitate convergence and accuracy. Numerical results are presented in the form of vector plots for purposes of general description and tables for comparison with experiment. Agreement with experiment is good. However experimental results, for comparison are available only in the vanes. In the vaneless section of the volute, the converged solution depicts some interesting secondary flow features — in regions inaccesible to the current experimental measurements.

scholarly journals Computational Study of Transverse Slot Injection in Supersonic Flow

2018 ◽  
Vol 68 (2) ◽  
pp. 121 ◽  
Author(s):  
Malsur Dharavath ◽  
P. Manna ◽  
Debasis Chakraborty
Keyword(s):  
Supersonic Flow ◽  
Stokes Equations ◽  
Computational Study ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Injection Pressure ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Scramjet Combustor ◽  
Flow Features

The knowledge of transverse sonic injection flow field is very important for the design of scramjet combustor. Three dimensional Reynolds-Averaged Navier Stokes equations alongwith turbulence models are solved to find the effect of transverse sonic slot injection into a supersonic flow. Grid sensitivity of the results is studied for various structured grids. Simulations with different turbulence models (i.e., k-ε, k-ω, SST-kω, and RNG-kε) reveals that RNG-kε turbulence model better predicts the flow features. Computational fluid dynamics predicted wall pressure distribution for various injection pressures matches well with experimental data. The extent of upstream separated region increases with the increase of the injection pressure. The increase of slot width makes the interaction between transverse jet and free stream more intense and causes more spreading and penetration of injectant in the downstream region.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

scholarly journals Dynamics of Single Droplet Splashing on Liquid Film by Coupling FVM with VOF

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 841
Author(s):  
Yuzhen Jin ◽  
Huang Zhou ◽  
Linhang Zhu ◽  
Zeqing Li
Keyword(s):  
Liquid Film ◽  
Weber Number ◽  
Stokes Equations ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Single Droplet ◽  
Navier Stokes Equations ◽  
Volume Method ◽  
The Relationship

A three-dimensional numerical study of a single droplet splashing vertically on a liquid film is presented. The numerical method is based on the finite volume method (FVM) of Navier–Stokes equations coupled with the volume of fluid (VOF) method, and the adaptive local mesh refinement technology is adopted. It enables the liquid–gas interface to be tracked more accurately, and to be less computationally expensive. The relationship between the diameter of the free rim, the height of the crown with different numbers of collision Weber, and the thickness of the liquid film is explored. The results indicate that the crown height increases as the Weber number increases, and the diameter of the crown rim is inversely proportional to the collision Weber number. It can also be concluded that the dimensionless height of the crown decreases with the increase in the thickness of the dimensionless liquid film, which has little effect on the diameter of the crown rim during its growth.

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