玉米粉的品质改良

玉米作为主食材料其淀粉呈多角形,蛋白质中缺少醇溶谷蛋白,不能形成粘弹性面团,限制了其应用,产品形式较少,口感较粗糙。对玉米粉进行改性处理,使其具有与小麦粉类似的加工性质,从而开发更多的产品,充分利用玉米的营养,扩大玉米粉的应用范围,改善产品的食用品质。     

川东北元坝地区长兴组生物礁滩体系分频特征研究

川东北元坝地区二叠系长兴组生物礁滩埋藏深、横向变化大,用常规方法预测生物礁滩体描述困难。基于短时窗离散傅里叶变换的分频技术以及井震结合,确定了不同沉积相对应的频率范围,在此基础上刻画出了生物礁随频率变化的形态和平面展布特征,划分和确定了岩性油藏边界,为该区油气藏勘探提供了科学依据。      

一种高效的准二维管道瞬变流计算方法

为了提高准二维管道瞬变流模型的计算效率,对现有的基于特征线法的准二维模型的算法进行了改进,提出了直接利用一维显式方程计算管道的流量和压力,取代了原算法中需通过数值积分求解平均速度再进一步计算节点压力的方法。该文提出的一维显式方程采用FVS （Flux Vector Splitting）方法,并在水库-管道-阀门系统中,将该方法与两个现有的准二维模型的算法在准确性和计算效率方面进行了比较。结果表明:该文所提出的方法与另外两个算法得到的计算结果基本相同,但是所花费的计算时间更少。因此,该文所提出的方法是一种计算准确并且高效的准二维瞬变流计算方法,适用于管道系统瞬变流的数值模拟分析。     

Numerical Simulation for Two-Phase Water Hammer Flows in Pipe by Quasi-Two-Dimensional Model

The features of a quasi-two-dimensional (quasi-2D) model for simulating two-phase water hammer flows with vaporous cavity in a pipe are investigated. The quasi-2D model with discrete vaporous cavity in the pipe is proposed in this paper. This model uses the quasi-2D model for pure liquid zone and one-dimensional (1D) discrete vapor cavity model for vaporous cavity zone. The quasi-2D model solves two-dimensional equations for both axial and radial velocities and 1D equations for both pressure head and discharge by the method of characteristics. The 1D discrete vapor cavity model is used to simulate the vaporous cavity occurred when the pressure in the local pipe is lower than the vapor pressure of the liquid. The proposed model is used to simulate two-phase water flows caused by the rapid downstream valve closure in a reservoir-pipe-valve system. The results obtained by the proposed model are compared with those by the corresponding 1D model and the experimental ones provided by the literature, respectively. The comparison shows that the maximum pressure heads simulated by the proposed model are more accurate than those by the corresponding 1D model.     

An advanced hybrid method for the acoustic prediction

The present article proposes an advanced methodology for numerically simulating complex noise problems. More precisely, we consider the so-called multi-stage acoustic hybrid approach, which principle is to couple sound generation and acoustic propagation stages. Under that approach, we propose an advanced hybrid method which acoustic propagation stage relies on Computational AeroAcoustics (CAA) techniques. To this end, first, an innovative weak-coupling technique is developed, which allows an implicit forcing of the CAA stage with a given source signal coming from an a priori evaluation, whether the latter evaluation is of analytical or computational nature. Then, thanks to additional innovative solutions, the resulting CAA-based hybrid approach is optimized so that it can be applied to realistic and complex acoustic problems in an easier and safer way. All these innovative features are then validated on the basis of an academic test case, before the resulting advanced CAA-based hybrid methodology is applied to two problems of flow-induced noise radiation. This demonstrates the ability of the here proposed method to address realistic problems, by offering to handle at the same time both acoustic generation and propagation phenomena, despite their intrinsic multiscale character.