scholarly journals Numerical visualization of drop and opening process for parachute-payload system adopting fluid–solid coupling simulation

2021 ◽  
Author(s):  
Binqi Chen ◽  
Yiding Wang ◽  
Chendi Zhao ◽  
Yi Sun ◽  
Leiming Ning
Keyword(s):  
Kinetic Characteristic ◽  
Aerodynamic Characteristics ◽  
Arbitrary Lagrangian Eulerian ◽  
Numerical Visualization ◽  
Mesh Method ◽  
Calculation Results ◽  
Motion Characteristic ◽  
Opening Load ◽  
Opening Stage ◽  
Moving Fluid

AbstractIn order to study the fluid–solid coupling dynamic characteristics of parachute-payload system during drop process and analyze the unsteady aerodynamic characteristics under finite mass opening conditions, an adaptive moving fluid mesh method is developed on the basis of the existing arbitrary Lagrangian–Eulerian (ALE) fluid–solid coupling method. The calculation results of open force and drop velocity on the C-9 parachute demonstrate the effectiveness of this method. On this basis, the effect of canopies with three different permeability on parachute-payload system motion characteristic including opening property, steady descent property and stability is studied. Comparative analysis is conducted for structures and characteristics of vortex with different canopy materials, and interference mechanism of unsteady flow for parachute-payload system in unsteady oscillation is revealed. The results show that the adaptive moving fluid mesh method can effectively eliminate restrictions of existing simulation methods for parachute-payload system and significantly reduce calculation time. For the lightweight parachute, permeability has significant effect on kinetic characteristic of parachute-payload system. Canopy with large permeability has small opening load and structural stress in opening stage. After opening, there are mainly small vortexes distributed evenly behind the canopy with good stability. However, canopy with small permeability has obvious breath behavior and oscillation in opening stage. The main vortexes periodically shed off after opening. With the change of permeability from small to large, Parachute-payload system eventually presents three steady descent modes: conical descent, gliding descent and stable vertical descent. Graphical abstract

scholarly journals The Numerical Simulation of UAV's Landing in Ship Airwake

2019 ◽  
Vol 37 (1) ◽  
pp. 186-194
Author(s):  
Xu Li ◽  
Xiaoping Zhu ◽  
Zhou Zhou ◽  
Xiaoping Xu
Keyword(s):  
Safety Assessment ◽  
Dynamic Pressure ◽  
Aerodynamic Characteristics ◽  
Flow Fields ◽  
Coupled Flow ◽  
Aircraft Carrier ◽  
Mesh Method ◽  
Calculation Results ◽  
Time Average ◽  
Boundary Layer Mesh

In order to investigate the influence of ship airwake on aerodynamic characteristics of the carrier-based aircraft, UAV's landings in different winds over deck were simulated by Overset Mesh method. Firstly, mesh factors, steady and unsteady methods were compared based on single aircraft carrier. The results showed that the boundary layer mesh around ship didn't show obvious influence for our simulation, and the calculation results between the steady and unsteady time average showed a similar trend. Then, aircraft carrier's flow fields in three wind directions were analyzed, and ship airwake variations with different direction winds over deck were concluded as well. Next, the reliability of Overset Mesh was verified though single UAV's landing simulation. Finally, the coupled flow fields of UAV/ship were studied. The calculation results indicated that aircraft was always in a low dynamic pressure condition, the lift and pitching moment of UAV had apparent changes in landing. Meanwhile, the aerodynamic fluctuations of UAV also revealed differences in different wind directions. The simulation results can be regarded as a reference for the safety assessment of carrier-based aircraft's landing and its control in the future.

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

Thermal-Mechanical Effect on Temperature/Stress Distribution when Orthogonal Cutting Bearing Steel

2009 ◽  
Vol 407-408 ◽  
pp. 420-423
Author(s):  
He Ping Wang ◽  
Xue Ping Zhang
Keyword(s):  
Stress Distribution ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Bearing Steel ◽  
Mechanical Effect ◽  
Arbitrary Lagrangian Eulerian ◽  
Calculation Results ◽  
On Chip ◽  
Explicit Dynamic

An explicit dynamic coupled thermal-mechanical Arbitrary Lagrangian Eulerian (ALE) model was established to simulate orthogonal cutting AISI 52100 bearing steel, and its temperature and stress distribution. Based on ABAQUS, The ALE approach effectively simulates plastic flow around round edge of the cutting tool without employing chip separation criteria. The calculation results reveal that cutting speed and cutting depth have great impact on chip morphology, stress and temperature distribution in the finished surface and subsurface, the predicted temperature agrees well with experiment data obtained under the similar cutting conditions as well as the change in chip morphology from continuous to sawtooth as the cutting speed increases.

scholarly journals Investigation on aerodynamic characteristics of bionic membrane nano rotor

2021 ◽  
Vol 18 ◽  
pp. 175682932110433
Author(s):  
Shanyong Zhao ◽  
Zhen Liu ◽  
Ke Lu ◽  
Dacheng Su ◽  
Shangjing Wu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Structural Parameters ◽  
Element Model ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Dynamics Model ◽  
Interaction Method ◽  
Calculation Results ◽  
The Finite Element Model

In this paper, the bionic membrane structure is introduced to improve the aerodynamic performance of nano rotor at the low Reynolds number. The aerodynamic characteristics of nano rotor made of hyperelastic material as membrane blades are studied. Firstly, based on the hyperelastic constitutive model, a finite element model of the rotor is established and compared with the results of the modal test to verify the accuracy of the model. Then the computational fluid dynamics model of membrane nano rotor is established which combined with the finite element model. The aerodynamic characteristics of the membrane rotor under hovering conditions are studied using fluid–structure interaction method. It is found that the calculation results matched well with the experiment results. The design of the structural parameters such as the membrane proportion, shape, and position of the membrane rotor is optimized. The influence of each parameter on the aerodynamic performance of the rotor is obtained. Under certain structural conditions, the performance can be effectively improved, which provides a new idea for the design of the nano rotor.

scholarly journals Numerical Simulation and Analysis of External Flow Field of the Van

2019 ◽  
Vol 293 ◽  
pp. 01001
Author(s):  
Kan Zhou ◽  
Ge Huang ◽  
Bin Liu ◽  
Qi Hu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Vortex Motion ◽  
Aerodynamic Characteristics ◽  
External Flow ◽  
Calculation Results

This paper uses CFD preprocessing software to build Van model and gridding it, then CFD software is used to simulation the outflow field of Van model, from which the distribution of pressure and velocity is obtained and the outflow field is analyzed. The calculation results indeed reflect the aerodynamic characteristics of the external flow field of the van, and the flow movement on the van surface is better simulated. In addition, the positions where the vortex motion is relatively severe are also found

scholarly journals Mesh moving techniques in fluid-structure interaction: robustness, accumulated distortion and computational efficiency

2020 ◽  
Author(s):  
Alexander Shamanskiy ◽  
Bernd Simeon
Keyword(s):  
Fluid Structure Interaction ◽  
Continuation Methods ◽  
Moving Mesh Method ◽  
Important Ingredient ◽  
Fluid Structure ◽  
Harmonic Extension ◽  
Structure Interaction ◽  
Computational Mesh ◽  
Mesh Method ◽  
Moving Fluid

AbstractAn important ingredient of any moving-mesh method for fluid-structure interaction (FSI) problems is the mesh moving technique (MMT) used to adapt the computational mesh in the moving fluid domain. An ideal MMT is computationally inexpensive, can handle large mesh motions without inverting mesh elements and can sustain an FSI simulation for extensive periods of time without irreversibly distorting the mesh. Here we compare several commonly used MMTs which are based on the solution of elliptic partial differential equations, including harmonic extension, bi-harmonic extension and techniques based on the equations of linear elasticity. Moreover, we propose a novel MMT which utilizes ideas from continuation methods to efficiently solve the equations of nonlinear elasticity and proves to be robust even when the mesh undergoes extreme motions. In addition to that, we study how each MMT behaves when combined with the mesh-Jacobian-based stiffening. Finally, we evaluate the performance of different MMTs on a popular two-dimensional FSI benchmark reproduced by using an isogeometric partitioned solver with strong coupling.

Aerodynamic Design of a Power Turbine for an Aircraft Derivative Marine Gas Turbine

1988 ◽  
Vol 110 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Guiming Ji ◽  
Zengxiang Tan ◽  
Mingchang Zhang
Keyword(s):  
Gas Turbine ◽  
Design Methodology ◽  
Aerodynamic Characteristics ◽  
Engineering Practice ◽  
Variable Geometry ◽  
Aerodynamic Design ◽  
Gas Generator ◽  
Power Turbine ◽  
Calculation Results ◽  
Radial Equilibrium

Based on the aerodynamic design and development of a power turbine for an aircraft derivative marine gas turbine in our engineering practice and taking account of the specific features of a marinization effort, this paper describes the design approach and aerodynamic characteristics of the said power turbine, including parameter selection, design methodology, comparison of flow calculation results obtained by simple radial equilibrium and full radial equilibrium method, and a versatile design of the power turbine capable of rendering two power ratings. Also described is the use of variable geometry stator blades to accommodate a small amount of adjustment to the gas generator outlet parameters.

Unsteady Aerodynamic Characteristics of a High Speed Train with Crosswind

2011 ◽  
Vol 66-68 ◽  
pp. 1878-1882
Author(s):  
Ming Lu Zhang ◽  
Yi Ren Yang ◽  
Chen Guang Fan ◽  
Li Lu
Keyword(s):  
Wind Tunnel ◽  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Vehicle Speed ◽  
High Speed Train ◽  
Mesh Method

The aerodynamic performances of a high speed train will significant change under the action of the crosswind. Large eddy simulation (LES) was made to solve the flow around a simplified CRH2 high speed train with 250km/h and 350km/h under the influence of a crosswind with 28.4m/s base on the finite volume method and dynamic layering mesh method and three dimensional incompressible Navier-Stokes equations. Wind tunnel experimental method of static train with relative flowing air and dynamic mesh method of moving train were compared. The results of numerical simulation show that the flow field around train is completely different between Wind tunnel experiment and factual running. Many vortices will be produced on the leeside of the train with alternately vehicle bottom and back under the influence of a crosswind. The flow field around train is similar with different vehicle speed.

Aerodynamic Characteristics Simulation Analysis of a Certain Type Changed Wing Drone Aircraft Based on CFD

2014 ◽  
Vol 644-650 ◽  
pp. 746-750
Author(s):  
De You Ma ◽  
Ming Xu ◽  
Zhao Tao Chen
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Type Model ◽  
Flight Performance ◽  
Flight Data ◽  
Simulation Calculation ◽  
Calculation Results ◽  
Conventional Type

This paper aims at the change of the whole machine aerodynamic characteristics after a certain conventional type drone aircraft changing plateau type large wings , using CFD technology to establish the nomal type and plateau type model, doing numerical simulation calculation of the whole machine's aerodynamic performance under the condition of no-load, using the simulation calculation results and combined with actual flight data, compared and evaluated the aerodynamic characteristics of the drone aircraft installed different airfoil, the results show that change plateau type large wings, obviously improve the lift-to-drag performance of the whole machine, increase the range of effective attack angle, and the little change of flight performance, scientific and feasible.

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