Fluent中湍流強度(Turbulence Intensity)的基本定義和理解

2022-12-29  by:CAE仿真在線(xiàn)  來(lái)源:互聯(lián)網(wǎng)

關(guān)于的基本公式是這樣的:


Fluent中湍流強度(Turbulence Intensity)的基本定義和理解fluent圖片1

稍微解釋一下就是

1、他是一種比值,衡量的是湍流的程度,所以fluent后面給他帶了個(gè)單位是%,百分比的單位

2、他是用來(lái)衡量湍流的程度的,所以并不是兩個(gè)速度的比值,而是速度波動(dòng)程度相對于平均速度的比值。而速度波動(dòng)描述的就是湍流的特征。

這個(gè)值會(huì )因為采用模型不同而有不同,一般10%一下算是較小的,而20%算是較大的,但是也有300%及其以上的,比如流速變化劇烈的局部區域,這也不奇怪。

下面是具體來(lái)源和官方的解釋:


https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v181/en/flu_ug/x1-4300008.63.2.html

文檔位置:help/flu_ug/x1-4300008.63.2.html


Fluent中湍流強度(Turbulence Intensity)的基本定義和理解fluent仿真分析圖片2



7.4.2.1.3. Turbulence Intensity
The turbulence intensity, , is defined as the ratio of the root-mean-square of the velocity fluctuations, , to the mean flow velocity, .

A turbulence intensity of 1% or less is generally considered low and turbulence intensities greater than 10% are considered high. Ideally, you will have a good estimate of the turbulence intensity at the inlet boundary from external, measured data. For example, if you are simulating a wind-tunnel experiment, the turbulence intensity in the free stream is usually available from the tunnel characteristics. In modern low-turbulence wind tunnels, the free-stream turbulence intensity may be as low as 0.05%.

For internal flows, the turbulence intensity at the inlets is totally dependent on the upstream history of the flow. If the flow upstream is under-developed and undisturbed, you can use a low turbulence intensity. If the flow is fully developed, the turbulence intensity may be as high as a few percent. The turbulence intensity at the core of a fully-developed duct flow can be estimated from the following formula derived from an empirical correlation for pipe flows:

Fluent中湍流強度(Turbulence Intensity)的基本定義和理解fluent圖片1(7–71)
At a Reynolds number of 50,000, for example, the turbulence intensity will be 4%, according to this formula.

The default value for turbulence intensity is 5% (medium intensity).



開(kāi)放分享:優(yōu)質(zhì)有限元技術(shù)文章,助你自學(xué)成才

相關(guān)標簽搜索:Fluent中湍流強度(Turbulence Intensity)的基本定義和理解 Fluent培訓 Fluent流體培訓 Fluent軟件培訓 fluent技術(shù)教程 fluent在線(xiàn)視頻教程 fluent資料下載 fluent分析理論 fluent化學(xué)反應 fluent軟件下載 UDF編程代做 Fluent、CFX流體分析 HFSS電磁分析 

編輯
在線(xiàn)報名:
  • 客服在線(xiàn)請直接聯(lián)系我們的客服,您也可以通過(guò)下面的方式進(jìn)行在線(xiàn)報名,我們會(huì )及時(shí)給您回復電話(huà),謝謝!
驗證碼

全國服務(wù)熱線(xiàn)

1358-032-9919

廣州公司:
廣州市環(huán)市中路306號金鷹大廈3800
電話(huà):13580329919
          135-8032-9919
培訓QQ咨詢(xún):點(diǎn)擊咨詢(xún) 點(diǎn)擊咨詢(xún)
項目QQ咨詢(xún):點(diǎn)擊咨詢(xún)
email:kf@1cae.com