Numerical modeling of data center with transient boundary conditions

2010 ◽  
Author(s):  
Srujan Gondipalli ◽  
Mahmoud Ibrahim ◽  
Siddharth Bhopte ◽  
Bahgat Sammakia ◽  
Bruce Murray ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Data Center

Upon Impact Numerical Modeling of Foam Materials

2017 ◽  
Vol 54 (2) ◽  
pp. 195-202
Author(s):  
Vasile Nastasescu ◽  
Silvia Marzavan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Analysis ◽  
Numerical Methods ◽  
Boundary Conditions ◽  
General Character ◽  
Foam Material ◽  
Various Boundary Conditions ◽  
Specific Behaviour

The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.

scholarly journals Numerical Modeling of the Motion of the Flat Textile Structures

2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
Piotr Szablewski
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Discrete Model ◽  
Gravity Force ◽  
Dynamic Conditions ◽  
Textile Structure ◽  
Sewing Thread ◽  
Lagrange’S Equations ◽  
Lagrange's Equations ◽  
Time Boundary

In many problems from the field of textile engineering (e.g., fabric folding, motion of the sewing thread) it is necessary to investigate the motion of the objects in dynamic conditions, taking into consideration the influence of the forces of inertia and changing in the time boundary conditions. This paper deals with the model analysis of the motion of the flat textile structure using Lagrange's equations in two variants: without constraints and with constraints. The motion of the objects is under the influence of the gravity force. Lagrange's equations have been used for discrete model of the structure.

Prediction of Hot Aisle Partition Airflow Boundary Conditions

2013 ◽  
Author(s):  
Zhihang Song ◽  
Bruce T. Murray ◽  
Bahgat Sammakia
Keyword(s):  
Boundary Conditions ◽  
Data Center ◽  
Computation Time ◽  
Design Tool ◽  
Operating Conditions ◽  
Ann Model ◽  
Flow Rates ◽  
Level Model ◽  
Optimization Methodology ◽  
Artificial Neural Network Ann

The integration of a simulation-based Artificial Neural Network (ANN) with a Genetic Algorithm (GA) has been explored as a real-time design tool for data center thermal management. The computation time for the ANN-GA approach is significantly smaller compared to a fully CFD-based optimization methodology for predicting data center operating conditions. However, difficulties remain when applying the ANN model for predicting operating conditions for configurations outside of the geometry used for the training set. One potential remedy is to partition the room layout into a finite number of characteristic zones, for which the ANN-GA model readily applies. Here, a multiple hot aisle/cold aisle data center configuration was analyzed using the commercial software FloTHERM. The CFD results are used to characterize the flow rates at the inter-zonal partitions. Based on specific reduced subsets of desired treatment quantities from the CFD results, such as CRAC and server rack air flow rates, the approach was applied for two different CRAC configurations and various levels of CRAC and server rack flow rates. Utilizing the compact inter-zonal boundary conditions, good agreement for the airflow and temperature distributions is achieved between predictions from the CFD computations for the entire room configuration and the reduced order zone-level model for different operating conditions and room layouts.

scholarly journals Past and current sediment dispersion pattern estimates through numerical modeling of wave climate: an example of the Holocene delta of the Doce River, Espírito Santo, Brazil

2007 ◽  
Vol 79 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Abílio C.S.P. Bittencourt ◽  
José M.L. Dominguez ◽  
Louis Martin ◽  
Iracema R. Silva ◽  
Karla O.P. de-Medeiros
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Late Holocene ◽  
Climate Model ◽  
Coastal Region ◽  
Wave Climate ◽  
Aerial Photographs ◽  
Dispersion Pattern ◽  
Dispersion Patterns ◽  
Doce River

This paper presents a numerical modeling estimation of the sediment dispersion patterns caused by waves inciding through four distinct coastline contours of the delta plain of the Doce River during the Late Holocene. For this, a wave climate model based on the construction of wave refraction diagrams, as a function of current boundary conditions, was defined and was assumed to be valid for the four coastlines. The numerical modeling was carried out on basis of the refraction diagrams, taking into account the angle of approximation and the wave height along the coastline. The results are shown to be comparable with existing data regarding the directions of net longshore drift of sediments estimated from the integration of sediment cores, interpretation of aerial photographs and C14 datings. This fact apparently suggests that, on average, current boundary conditions appear to have remained with the same general characteristics since 5600 cal yr BP to the present. The used approach may prove useful to evaluate the sediment dispersion patterns during the Late Holocene in the Brazilian east-northeast coastal region.

A Multi-Zone Building Energy Simulation of a Data Center Model With Hot and Cold Aisles

2013 ◽  
Author(s):  
Long Phan ◽  
Cheng-Xian Lin ◽  
Mirko Schäfer
Keyword(s):  
Energy Consumption ◽  
Boundary Conditions ◽  
Data Center ◽  
Building Energy ◽  
Energy Simulation ◽  
Building Energy Simulation ◽  
Simulation Code ◽  
Climate Conditions ◽  
Wall Boundary ◽  
Wall Boundary Conditions

In this paper, a building energy simulation code, EnergyPlus, was used to study selected important conditions, i.e. wall boundary conditions and locations, which potentially affect the energy consumption and thermal management of a popular data center model. The data center model having 1120 servers distributed in four rows of rack was investigated under two major climate conditions — hot and humid (Miami, FL), and cool and humid (Chicago, IL), and under five different wall boundary conditions. The data center model was first simulated under a well-mixed single-zone condition as a baseline. Then, a multi-zone approach was proposed to resolve the hot and cold aisles and used to investigate the data center performance. Both monthly and annual overall energy consumption as well as cooling load reports were analyzed and compared among various boundary conditions. In addition, monthly thermal behavior of hot and cold aisle zones within the data center was analyzed. The simulation results show that thermal performance of the data center is significantly affected by locations or climate conditions. The effects of location and wall boundary conditions are particularly appreciable during the summer and winter seasons.

Analysis of Airflow Distribution Across a Front-to-Rear Server Rack

2007 ◽  
Author(s):  
Amir Radmehr ◽  
Kailash C. Karki ◽  
Suhas V. Patankar
Keyword(s):  
Boundary Conditions ◽  
Data Center ◽  
High Velocity ◽  
Critical Conditions ◽  
Airflow Distribution ◽  
Symmetrical Configuration ◽  
Computational Fluid Dynamics Cfd ◽  
Potential Failure ◽  
Cooling Air ◽  
Vertical Jet

The most common server racks in data centers are front-to-rear racks, which draw in the cooling air from the front side and discharge it from the backside. In a raised-floor data center the cooling air to these racks is provided by perforated tiles that are placed in front of them. In a high-density data center, these tiles discharge a considerable amount of airflow, which leads to a high-velocity vertical jet in front of the rack. Such a high-velocity jet may bypass the servers located at the bottom of the rack leading to their airflow starvation and potential failure. In this paper the effect of the high-velocity jet on the airflow taken by servers at various heights in the rack is studied. A computer model based on the Computational Fluid Dynamics (CFD) technique is used to predict the airflow distribution through servers stacked in the rack. Two cases are considered. In one case, the rack is placed in the middle of a row of racks in a prefect hot aisle-cold aisle arrangement. The boundary conditions around such a rack is symmetrical. In the other case, the rack is placed in a room with asymmetrical boundary conditions. The characteristics of the servers in the rack are taken from typical 1U and 2U servers manufactured by IBM. It is shown that in general the high-velocity jet has a mild effect on the airflow taken by the servers, and the airflow reduction is limited to servers at the bottom of the rack. Racks in a symmetrical configuration are more susceptible to the airflow starvation. In the most critical conditions, an airflow reduction of 15% is calculated for the server located at the bottom of the rack. Using the result obtained from the computational analysis, a simple model is developed to predict the reduction of the cooling air under the most critical situation for the server placed at the bottom of the rack.

Numerical modeling of multiple length scales in thermal transport processes

2014 ◽  
Vol 24 (4) ◽  
pp. 781-796 ◽  
Author(s):  
Yogesh Jaluria
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Time Scales ◽  
Transport Processes ◽  
Thermal Processes ◽  
Length Scales ◽  
Content Type ◽  
Multiple Length Scales ◽  
Wide Range ◽  
Simulation Results

Purpose – Multiple length and time scales arise in a wide variety of practical and fundamental problems. It is important to obtain accurate and validated numerical simulation results, considering the different scales that exist, in order to predict, design and optimize the behavior of practical thermal processes and systems. The purpose of this paper is to present modeling at the different length scales and then addresses the question of coupling the different models to obtain the overall model for the system or process. Design/methodology/approach – Both numerical and experimental methods to obtain results at the different length scales, particularly at micro and nanoscales, are considered. Even though the paper focusses on length scales, multiple time scales lead to similar concerns and are also considered. The two circumstances considered in detail are multiple length scales in different domains and those in the same domain. These two cases have to be modeled quite differently in order to obtain a model for the overall process or system. The basic considerations involved in such a modeling are discussed. A wide range of thermal processes are considered and the methods that may be used are presented. The models employed must be validated and the accuracy of the simulation results established if the simulation results are to be used for prediction, control and design. Findings – Of particular interest are concerns like verification and validation, imposition of appropriate boundary conditions, and modeling of complex, multimode transport phenomena in multiple scales. Additional effects such as viscous dissipation, surface tension, buoyancy and rarefaction that could arise and complicate the modeling are discussed. Uncertainties that arise in material properties and in boundary conditions are also important in design and optimization. Large variations in the geometry and coupled multiple regions are also discussed. Research limitations/implications – The paper is largely focussed on multiple-scale considerations in thermal processes. Both numerical modeling/simulation and experimentation are considered, with the latter being used for validation and physical insight. Practical implications – Several examples from materials processing, environmental flows and electronic systems, including data centers, are given to present the different techniques that may be used to achieve the desired level of accuracy and predictability. Originality/value – Present state of the art and future needs in this interesting and challenging area are discussed, providing the impetus for further work. Different methods for treating multiscale problems are presented.

Sign in / Sign up

Export Citation Format

Share Document