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Technological advances in simulation software have opened up new opportunities for accurate modeling of flow-induced noise and vibration across a broad frequency range. Additionally, new methods have been implemented that can be used to model vibroacoustic phenomena more efficiently. This seminar provides an overview of recently implemented methods and discusses various applications..
Measuring the Value and Cost of Data Analysis
Is a picture worth a thousand words? Some are, some aren’t — but why? When it comes to presenting simulation results, it is not an easy question to answer or anticipate. While we are fully engaged in projects, we learn a lot about the devices and processes we are modeling. With excessive amounts of data being generated in the face of fast-approaching deadlines and our target audiences needing to form their own thousand-word narratives, it is easy to lose sight of our primary objective: delivering something in an efficient and effective way that enables others to see problems immediately and...
Imagine achieving better product designs, faster and with less testing or doing a lot of manual work. That kind of workflow process and capability is here, now. To experience this for yourself, we are pleased to invite you to a complimentary workshop that will show you how easy design exploration can be. Whether you are new to any field of engineering simulation or experienced in computer-aided design, this session will bring helpful insight into how simulation adds more value to your projects.
Stage Separation of Ares-1X Vehicle showing plume and flow around the vehicle using Overset Mesh technology
SCR系统中结晶问题的数值研究
选择性催化还原(SCR)技术在工业界中得到了广泛的应用,该技术主要用于减少柴油机中氮氧化物的排放,以满足排放法规的要求。设计一个高效的SCR系统,需要符合许多重要的标准,这其中包括准备液态氨水的快速混合以及SCR设备中氨分布的均匀性。 然而,结晶问题一直威胁着SCR系统的使用寿命和性能。结晶会产生背压,腐蚀材料,这大大降低了SCR系统的性能,从而影响发动机的正常工作。 使用模拟的手段,可以优化SCR设备的设计,从而降低氮氧化物的排放,减少结晶产生,满足法规的要求。 本次在线讲座将会介绍SCR设备模拟中使用的最新的技术,以及如何提高计算的精度。演讲嘉宾将会展示如何使用CFD的手段,更好的理解液相,湍流流场和排气系统中热面的相互作用,以及结晶对SCR设备的影响。
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...

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