Numerical Analysis of the LCS 2 airwake to understand potential interactions during helipcopter operations

2015 ◽  
Author(s):  
Brent S. Paul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Flow Field ◽  
Ship Design ◽  
It Impacts ◽  
Flight Envelope ◽  
Computational Fluid Dynamics Cfd ◽  
Potential Interactions ◽  
Flight Deck

The successful integration of aviation capabilities aboard ships is a complex endeavor that must balance ship design with the flight envelope of the helicopter. This can be particularly important when considering air wakes and other flow around the superstructure as it impacts the flight deck. This flow can generate unsteady structures that may interfere with safe helicopter operations. Computational fluid dynamics (CFD) is commonly used to characterize the flow field and assess potential impacts to the flight envelope, which can be used to help define an operating envelope for helicopter operations.

Construction Ventilation Scheme Optimization of Underground Main Powerhouse Based on CFD

2013 ◽  
Vol 368-370 ◽  
pp. 619-623
Author(s):  
Zhen Liu ◽  
Xiao Ling Wang ◽  
Ai Li Zhang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Air Flow ◽  
Scheme Optimization ◽  
Pressure Distributions ◽  
Air Volume ◽  
Computational Fluid Dynamics Cfd ◽  
Traditional Construction ◽  
Ventilation Scheme

For the purpose of avoiding the deficiency of the traditional construction ventilation, the ventilation of the underground main powerhouse is simulated by the computational fluid dynamics (CFD) to optimize ventilation parameters. A 3D unsteady RNG k-ε model is performed for construction ventilation in the underground main powerhouse. The air-flow field and CO diffusion in the main powerhouse are simulated and analyzed. The two construction ventilation schemes are modelled for the main powerhouse. The optimized ventilation scheme is obtained by comparing the air volume and pressure distributions of the different ventilation schemes.

scholarly journals Effect of Doppler flow meter position on discharge measurement in surcharged manholes

2017 ◽  
Vol 77 (3) ◽  
pp. 647-654 ◽  
Author(s):  
Haoming Yang ◽  
David Z. Zhu ◽  
Yanchen Liu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Flow Regimes ◽  
Flow Meter ◽  
Flow Meters ◽  
Flow Discharge ◽  
Doppler Flow ◽  
Sewer Systems ◽  
Computational Fluid Dynamics Cfd

Abstract Determining the proper installation location of flow meters is important for accurate measurement of discharge in sewer systems. In this study, flow field and flow regimes in two types of manholes under surcharged flow were investigated using a commercial computational fluid dynamics (CFD) code. The error in measuring the flow discharge using a Doppler flow meter (based on the velocity in a Doppler beam) was then estimated. The values of the corrective coefficient were obtained for the Doppler flow meter at different locations under various conditions. Suggestions for selecting installation positions are provided.

CFD Leakage Predictions of Unworn and Worn Labyrinth Seals With and Without Tooth Axial Offset

2017 ◽  
Author(s):  
Hasham H. Chougule ◽  
Alexander Mirzamoghadam
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Steady State ◽  
Flow Field ◽  
Labyrinth Seals ◽  
Small Clearance ◽  
Total Leakage ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Deflection

The objective of this study is to develop a Computational Fluid Dynamics (CFD) based methodology for analyzing and predicting leakage of worn or rub-intended labyrinth seals during operation. The simulations include intended tooth axial offset and numerical modeling of the flow field. The purpose is to predict total leakage through the seal when an axial tooth offset is provided after the intended/unintended rub. Results indicate that as expected, the leakage for the in-line worn land case (i.e. tooth under rub) is higher compared to unworn. Furthermore, the intended rotor/teeth forward axial offset/shift with respect to the rubbed land reduces the seal leakage. The overall leakage of a rubbed seal with axial tooth offset is observed to be considerably reduced, and it can become even less than a small clearance seal designed not to rub. The reduced leakage during steady state is due to a targeted smaller running gap because of tooth offset under the intended/worn land groove shape, higher blockages, higher turbulence and flow deflection as compared to worn seal model without axial tooth offset.

CFD Comparison of Clearance Flow in a Rotor-Casing Assembly Using Asymmetric vs. Symmetric Lobe Rotors

2003 ◽  
Author(s):  
Bassam Abu-Hijleh ◽  
Jiyuan Tu ◽  
Aleksander Subic ◽  
Huafeng Li ◽  
Katherine Ilie
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Mesh Generation ◽  
Cfd Analysis ◽  
Air Leakage ◽  
Flow Conditions ◽  
Leakage Path ◽  
Clearance Flow ◽  
Computational Fluid Dynamics Cfd

The performance of a Rotor-Casing Assembly is influenced more by the internal air leakages than by any other thermo-fluid aspect of its behaviour. The pressure difference driving the air along a leakage path varies periodically and does so in a manner that may not be the same for every leakage path. So the distribution of leakage through the various leakage paths within the machine is important for the improvement of its performance. The total volume of air leakage and the distribution of the leakage among the different paths depend on the rotor-rotor and rotor-casing clearances as well as the geometry of the rotors’ lobes. Computational Fluid Dynamics (CFD) analysis was carried out using the FLUENT. Geometry definition, mesh generation, boundary and flow conditions, and solver parameters have all been investigated as the part of the numerical analysis. This analysis was conducted for static rotors at different positions. The results indicate that the size of the clearances as well as the geometry of the rotors’ lobes can have a significant effect on the total volume of the air leakage as well as the distribution of the leakage among the three main leakage paths. The results can be used to ascertain the proper levels of clearances to be used and the best rotor lobes geometry to be used for the practical reduction of air leakage.

The Design of Refinement Criteria for Dynamic Grid Adaptation Applied to Airfoil Flow Modeling

2003 ◽  
Author(s):  
Melih Demir ◽  
Govert de With ◽  
Arne E. Holdo̸
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Unsteady Flow ◽  
Mesh Refinement ◽  
Research Centre ◽  
Shear Stresses ◽  
Wall Region ◽  
Grid Adaptation ◽  
Computational Fluid Dynamics Cfd

At present a large number of fluid dynamics applications are found in aerospace, civil and automotive engineering, as well in medical related fields. In many applications the flow field is turbulent and the computational modelling of such flows remains a difficult task. To resolve all turbulent flow phenomena for flow problems where turbulence is of key interest is a priori not feasible in a Computational Fluid Dynamics (CFD) investigation with a conventional mesh. The use of a Dynamic Grid Adaptation (DGA) algorithm in a turbulent unsteady flow field is an appealing technique which can reduce the computational costs of a CFD investigation. A refinement of the numerical domain with a DGA algorithm requires reliable criteria for mesh refinement which reflect the complex flow processes. At present not much work has been done to obtain reliable refinement criteria for turbulent unsteady flow. The purpose of the work is to implement a new refinement technique for the boundary layer in the vicinity of the wall. It is aimed to model the flow around an airfoil with a LES turbulence model and a new DGA algorithm. In addition to that several simulations have been carried out for parametric studies. In these studies the incompressible solver in REACFLOW has been used. This Computational Fluid Dynamics (CFD) code REACFLOW was developed in collaboration with the joint Research Centre (JRC) in Italy. The following aims are aspired: • A new mesh refinement criteria method suitable for boundary layers; • To carry out LES simulations to establish the performance of the refinement criteria. The new criteria which are created in this work are for the near wall region. This criteria uses the wall shear stresses for the refinement technique. For the main flow stream the refinement criteria proposed by de With et al [6] will be used.

Numerical Analysis of Flow Over the NASA Common Research Model Using the Academic Computational Fluid Dynamics Code Galatea

2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Computational Study ◽  
Research Model ◽  
Drag Forces ◽  
Efficient Prediction ◽  
Wind Tunnel Data ◽  
Computational Fluid Dynamics Cfd ◽  
Lift And Drag

A recently developed academic computational fluid dynamics (CFD) code, named Galatea, is used for the computational study of fully turbulent flow over the NASA common research model (CRM) in a wing-body configuration with and without horizontal tail. A brief description of code's methodology is included, while attention is mainly directed toward the accurate and efficient prediction of pressure distribution on wings' surfaces as well as of computation of lift and drag forces against different angles of attack, using an h-refinement approach and a parallel agglomeration multigrid scheme. The obtained numerical results compare close with both the experimental wind tunnel data and those of reference solvers.

STUDY OF AIRFLOW AROUND SHIP WITH RIGID SAIL ARRAY AND POTENTIAL ARRAY PROPULSIVE POWER

2021 ◽  
Vol 161 (A2) ◽  
Author(s):  
G M Atkinson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Ship Design ◽  
Fuel Oil ◽  
Cfd Analysis ◽  
Propulsive Force ◽  
Oil Consumption ◽  
Software Application ◽  
Computational Fluid Dynamics Cfd

An array of rigid sails installed on a large powered ship could provide a viable means to reduce fuel oil consumption (FOC) and emissions by using the power of the wind as a source of supplementary propulsion. This paper describes the study of airflow around a concept ship design fitted with 14 segment rigid sails (SRS) using a virtual wind tunnel software application and also investigates the propulsive force that a fixed sail array could provide using computational fluid dynamics (CFD) analysis.

Sign in / Sign up

Export Citation Format

Share Document