unsteady heat transfer

例句：

1. 1.The engine is unsteady due to the lack of fuel.
   由于燃料不足，发动机不稳定。
2. 2. The weather forecast for tomorrow is unsteady, so we should be prepared for any changes.
   明天的天气预报不稳定，所以我们应该为任何变化做好准备。
3. 3.The team's performance was unsteady during the game, which affected their overall results.
   球队在比赛中的表现不稳定，这影响了他们的总体成绩。