柱面坐標系
![柱面坐標變換](/img/f/fdb/wZwpmL4YTM0YTO5ITOwMzM1UTM1QDN5MjM5ADMwAjMwUzLykzL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/f/295/wZwpmL2ADNxQDOxcjNzYTN1UTM1QDN5MjM5ADMwAjMwUzL3YzL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
定義. 設P是中一點,在柱面坐標系中P的三個坐標變數是,其定義為
•徑向距離ρ是從z軸到點P的歐幾里得距離。
•方位角φ是所選平面上參照方向和從原點到平面上的P投影之間的直線之間的夾角。
•高度z是從所選平面到點P的有符號距離。
見圖1。
![圖1](/img/b/8b5/wZwpmL4QDO0gDM0YDOzYTN1UTM1QDN5MjM5ADMwAjMwUzL2gzL1EzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/f/295/wZwpmL2ADNxQDOxcjNzYTN1UTM1QDN5MjM5ADMwAjMwUzL3YzL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/b/5ef/wZwpmLxgjM0MDNzEzNzYTN1UTM1QDN5MjM5ADMwAjMwUzLxczLzgzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/f/22e/wZwpmL2ITN4cTN3MDNxUTN1UTM1QDN5MjM5ADMwAjMwUzLzQzLwYzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/a/e3f/wZwpmL1AzN1kDO3ATMwEDN0UTMyITNykTO0EDMwAjMwUzLwEzL4UzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
與極坐標類似, 柱坐標相同的同一點具有無限多個等效坐標, 即和,其中是任意整數。此外, 如果半徑為零,則方位角規定是任意的。
在某些情況下,需要為每個點設定唯一的坐標的情況下,可以將半徑限制為非負( ρ≥ 0) 和方位φ ,使其位於特定的間隔跨度,,如(−180°、+ 180 °) 或 [0,360°]
柱面坐標變換
![柱面坐標變換](/img/f/295/wZwpmL2ADNxQDOxcjNzYTN1UTM1QDN5MjM5ADMwAjMwUzL3YzL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/f/13e/wZwpmL2MDOzMTN5UTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL1EzLwAzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
柱面坐標系是三大常用的坐標系之一,其它二個常用的坐標系是標準的歐氏坐標系、球坐標系。柱面坐標變換公式描述了空間中一點P在柱面坐標系下的坐標與歐氏坐標系下的坐標之間的變換關係。該變換關係如下述公式給出 :
![柱面坐標變換](/img/4/768/wZwpmL2ATM1YDN5AzNzYTN1UTM1QDN5MjM5ADMwAjMwUzLwczLyEzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/f/295/wZwpmL2ADNxQDOxcjNzYTN1UTM1QDN5MjM5ADMwAjMwUzL3YzL1MzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/f/13e/wZwpmL2MDOzMTN5UTMzEzM1UTM1QDN5MjM5ADMwAjMwUzL1EzLwAzLt92YucmbvRWdo5Cd0FmLxE2LvoDc0RHa.jpg)
或者,將表達成的形式:
![柱面坐標變換](/img/b/ed7/wZwpmLygzNwczNzEzNzYTN1UTM1QDN5MjM5ADMwAjMwUzLxczLwgzLt92YucmbvRWdo5Cd0FmLwE2LvoDc0RHa.jpg)
![柱面坐標變換](/img/a/4df/wZwpmL4YDMwgDN4QTOzYTN1UTM1QDN5MjM5ADMwAjMwUzL0kzLwQzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
體積元
在許多套用中,柱面坐標系具有其它坐標系不具有的優點。了解在柱面坐標系的面積元,體積元是對我們有幫助的。
長度元:
![柱面坐標變換](/img/3/402/wZwpmL0MDO1gTN4czNxUTN1UTM1QDN5MjM5ADMwAjMwUzL3czL2gzLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)
面積元:
![柱面坐標變換](/img/4/dd4/wZwpmLzQTOwkjN0QDNxUTN1UTM1QDN5MjM5ADMwAjMwUzL0QzL0QzLt92YucmbvRWdo5Cd0FmLzE2LvoDc0RHa.jpg)
體積元:
![柱面坐標變換](/img/c/2e2/wZwpmL2gDM3IDN0kDOzYTN1UTM1QDN5MjM5ADMwAjMwUzL5gzLygzLt92YucmbvRWdo5Cd0FmLyE2LvoDc0RHa.jpg)
梯度、散度、旋度以及Laplace運算元在柱面坐標系下的由下述公式給出 :
![柱面坐標變換](/img/5/9f1/wZwpmL1ITM3kzM0IDOzYTN1UTM1QDN5MjM5ADMwAjMwUzLygzLyczLt92YucmbvRWdo5Cd0FmL0E2LvoDc0RHa.jpg)