二维纳维-斯托克方程的图形化描述方法

版权申诉
0 下载量 152 浏览量 更新于2024-10-25 收藏 2KB RAR 举报
资源摘要信息:"本文档主要关注如何使用二维坐标图形来描述纳维-斯托克(Navier-Stokes,简称NS)方程。NS方程是流体力学中描述流体运动的一组偏微分方程。在物理学中,它们是描述粘性流体动力学行为的基础。本文档将通过一个名为“2D NS2.py”的Python脚本,来展示如何在二维空间中构建和可视化NS方程。" 纳维-斯托克方程描述流体的运动,包括了流体速度场和压力场随时间和空间变化的规律。在工程、气象学、海洋学等多个领域都有广泛的应用。尽管NS方程在理论上得到了良好的发展,但它们的解析解在除了最简单情况之外很难获得。因此,数值方法成为了研究NS方程的重要工具。 在二维空间中,NS方程可以简化为两个主要方程,分别描述了水平和垂直方向上的流动,以及压力梯度。二维NS方程是三维NS方程的特殊情况,它们忽略了一个空间维度的流动,从而简化了计算的复杂性。 在实现NS方程的数值解时,可以使用多种方法,包括有限差分法、有限元法、谱方法等。Python作为一种广泛使用的高级编程语言,非常适合用来实现这些复杂的数值计算,并且借助matplotlib等库可以方便地将计算结果可视化。 Python脚本“2D NS2.py”可能是一个用以求解二维NS方程的数值模拟程序。这个脚本可能利用了Python中的NumPy库进行科学计算,SciPy库解决数学和工程问题,以及matplotlib库来绘制流场图等。该脚本可能包含以下几个关键部分: 1. 导入相关的Python库,如NumPy、SciPy、matplotlib等。 2. 定义空间域和时间域的参数,如网格尺寸、边界条件、初始条件等。 3. 设置时间步长以及总模拟时间。 4. 实现离散化NS方程的算法,如采用有限差分方法将连续的偏微分方程转化为离散的代数方程。 5. 在每个时间步长上更新流体的速度和压力,这通常涉及到求解线性或非线性方程组。 6. 利用matplotlib库将每次迭代后的流场进行可视化。 7. 最后,可能还会包含数据的保存以及后期处理等功能。 通过这样的脚本,研究者可以模拟出流体在特定条件下随时间变化的行为,通过可视化观察流场的特征,例如涡旋的形成、流动的稳定性等现象。这对于理解复杂流体力学行为和验证理论模型是非常有用的。 值得一提的是,尽管NS方程在理论上已经非常成熟,但它们的数值解法仍然充满挑战,尤其是在涉及到湍流等复杂现象时。因此,这样的模拟脚本在进行实际模拟时可能需要不断调试和优化,以确保模拟结果的准确性和计算效率。

class ASPP(nn.Module): def __init__(self, dim_in, dim_out, rate=1, bn_mom=0.1): super(ASPP, self).__init__() self.branch1 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 1, 1, padding=0, dilation=rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch2 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=4 * rate, dilation=4 * rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch3 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=8 * rate, dilation=8 * rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch4 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=12 * rate, dilation=12 * rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch5 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=16 * rate, dilation=16 * rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch6 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=20 * rate, dilation=20 * rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True) ) self.branch7 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=24 * rate, dilation=24 * rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True) ) self.branch8_conv = nn.Conv2d(dim_in, dim_out, 1, 1, 0, bias=True) self.branch8_bn = nn.BatchNorm2d(dim_out, momentum=bn_mom) self.branch8_relu = nn.ReLU(inplace=True) self.conv_cat = nn.Sequential( nn.Conv2d(dim_out * 8, dim_out, 1, 1, padding=0, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), )用1×3卷积和3×1卷积代替这段代码的3×3卷积

2023-06-09 上传

class ASPP(nn.Module) def init(self, dim_in, dim_out, rate=1, bn_mom=0.1) super(ASPP, self).init() self.branch1 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 1, 1, padding=0, dilation=rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch2 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=4 rate, dilation=4 rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch3 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=8 rate, dilation=8 rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch4 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=12 rate, dilation=12 rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch5 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=16 rate, dilation=16 rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) self.branch6 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=20 rate, dilation=20 rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True) ) self.branch7 = nn.Sequential( nn.Conv2d(dim_in, dim_out, 3, 1, padding=24 rate, dilation=24 rate, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True) ) self.branch8_conv = nn.Conv2d(dim_in, dim_out, 1, 1, 0, bias=True) self.branch8_bn = nn.BatchNorm2d(dim_out, momentum=bn_mom) self.branch8_relu = nn.ReLU(inplace=True) self.conv_cat = nn.Sequential( nn.Conv2d(dim_out 8, dim_out, 1, 1, padding=0, bias=True), nn.BatchNorm2d(dim_out, momentum=bn_mom), nn.ReLU(inplace=True), ) def forward(self, x) [b, c, row, col] = x.size() conv1x1 = self.branch1(x) conv3x3_1 = self.branch2(x) conv3x3_2 = self.branch3(x) conv3x3_3 = self.branch4(x) conv3x3_4 = self.branch5(x) conv3x3_5 = self.branch6(x) conv3x3_6 = self.branch7(x) global_feature = torch.mean(x, 2, True) global_feature = torch.mean(global_feature, 3, True) global_feature = self.branch8_conv(global_feature) global_feature = self.branch8_bn(global_feature) global_feature = self.branch8_relu(global_feature) global_feature = F.interpolate(global_feature, (row, col), None, 'bilinear', True) feature_cat = torch.cat([conv1x1, conv3x3_1, conv3x3_2, conv3x3_3, conv3x3_4, conv3x3_5, conv3x3_6, global_feature], dim=1) result = self.conv_cat(feature_cat) return result用1×3卷积和3×1卷积代替这段代码的3×3卷积

128 浏览量