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The harmonic balance method is a mixed time domain and frequency domain approach for efficiently solving periodic unsteady flows. The implementation described in this paper is designed to efficiently handle the multiple frequencies that arise within a multistage turbomachine due to differing blade counts in each blade row. We present two alternative algorithms that can be used to determine which unique set of frequencies to consider in each blade row. The first, an all blade row algorithm, retains the complete set of frequencies produced by a given blade row’s interaction with all other blade...
The harmonic balance method implemented within STARCCM+ is a mixed frequency/time domain computational fluid dynamic technique, which enables the efficient calculation of timeperiodic flows. The unsteady solution is stored at a small number of fixed time levels over one temporal period of the unsteady flow in a single blade passage in each blade row; thus the solution is periodic by construction. The individual time levels are coupled to one another through a spectral operator representing the time derivative term in the Navier-Stokes equation, and at the boundaries of the computational...
A nonlinear harmonic balance method for the simulation of turbomachinery flows is presented. The method is based on representing an unsteady, time periodic flow by a Fourier series in time and then solving a set of mathematically steady-state equations to obtain the Fourier coefficients. The steady-state solutions are stored at discrete time levels distributed throughout one period of unsteadiness and are coupled via the physical time derivative and at periodic boundaries. Implicit coupling between time levels is achieved in a computationally efficient manner through approximate factorization...
This work aims at presenting a numerical model to simulate the temperature and velocity fields in back compartment of a refrigerated semi-trailer. The cavity is ventilated by means of a ceiling evaporator. The air flow and temperature distributions in this ventilated enclosure are analysed from a CFD model. This model focuses on the jet development in the empty cavity. The influence of heat flux through the walls on the air temperature fields is observed. A parametric study regarding the blowing velocity is also presented. It shows that changing the velocity does not noticeably modify the air...
Modeling for Greater Insight with Harmonic Balance
Multi-stage turbomachinery flow-fields are inherently unsteady. Accurately capturing unsteady flow features such as tip vortex motion and blade-row interaction is important for properly predicting machine performance and thermal profiles. Modeling these unsteady features provides greater insight into the transient nature of the system, and is also necessary for accurate prediction of time-averaged quantities such as efficiency and blade temperature. Traditional time-marching unsteady methods are often accompanied by prohibitive expense with regard to computational cost. The harmonic balance...
Using CFD to Analyze Clean Rooms, Operating Rooms and Aseptic Filling Processes
Eliminating environmental or other airborne contaminants within medical, biological research and production facilities is critical to the success of their mission. The use of CFD allows for a non-intrusive way of determining air conditions of a room without concern for operator safety potentially disturbing a measurement. In this webcast we demonstrate how CFD is used for analysis and optimization in several environments: be it determining ventilation rates in an operating room, playing a critical role in minimizing the rate of infection from airborne bacteria and viruses; or a study of a...
DYNAMICS Japan, CD-adapco’s Simulation Magazine, Now Available Nagoya, a historical city and hometown of Shogun Tokugawa as well as the center of automotive and aerospace industries in Japan, is home to the third CD-adapco office location in Japan. New York, London and Yokohama. April 21, 2015 CD-adapco™, the largest privately held CFD-focused provider of Computer Aided Engineering software, today announced the opening of a third Japanese office location in Nagoya. CD-adapco already has well-established offices in Yokohama and Osaka. The company’s continued expansion into the Japanese market...
Retaining Dam CFD Analysis
Animation from BAW (Bundesanstalt für Wasserbau) showing a retaining dam at the river Neckar. Simulation performed for 50 s real time with 14.5 million cells.
STAR-CCM + v10.02 새로운 기능 소개
STAR-CCM +의 최신 버전 v10.02의 새로운 기능을 소개합니다. 본 온라인 강의에서는 2015 년 2 월 25 일 전세계에 동시 출시된 STAR-CCM + v10.02의 새로운 기능을 중심으로 소개합니다. 버전10.02에서는 다중 물리기반 설계 탐색 (MDX; Multidisciplinary Design eXploration)을 강화하고 설계 의사 결정을 빠르게 하여, 엔지니어들이 전체적인 운용 상황을 시뮬레이션 할 수 있도록 도와드립니다. 추가된 주요 기능은 다음과 같습니다. ・결과 처리 속도 향상: GPU를 활용한 그래픽 처리 속도 향상 ・맵핑 속도 향상: 데이터 매핑 속도의 비약적 향상 ・Large Scale Interface (LSI) 모델 오일러 다상 모델에 Large Scale Interface (LSI) 모델이 추가 되어 자유 표면, 스프레이, 기포를 하나의 모델에서 작업할 수 있습니다. ・Adjoint Method를 통한 오차 평가 기능: 해석 모델에서 격자의 이산화 오류를 강조하기 위해 Adjoint Method를 사용한 오차 평가 기능을 추가 ・Multiphase 기능 향상: VOF, Fluid Film, 그리고...
Accelerating Electronics Cooling Simulations with Automation
No CFD simulation is ever fast enough - anyone who has used CFD likely will agree with that. Most of the time the computing speed comes to mind when you state this, but the overall CAD-to-results time is actually a better measure. This webcast explores the use of automation tools to accelerate user interactive tasks when running electronics cooling simulations. Various methods of automating portions or all of your simulations are discussed, including templates and macros. Several examples to aid problem setup and results viewing is shown and advanced uses of these tools is introduced. The CAD...

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