What are these dunes ?

Humm, looking at these shifting sanddunes, it looks like southwards we will now be running into headwinds ! This is bad planning of ours, and was not taken into account. The desert is splendid here. we'll have time to enjoy ! By the way, we are not sure to remember the name of these dunes ? Anybody knows it ?

En regardant ces dunes, l'on comprend que nous affrontons maintenant des vents contraires... voila qui va un petit peu ralentir notre progression. Elles sont belles, ces dunes, mais quelqu'un saurait il nous dire comment elles s'appellent ??